It takes rather more than a bit of disinfectant, a bevy of orderlies and a little elbow grease to keep a big hospital spick and span. Malcolm Macalister Hall joins the frontline in the never-ending battle against dirt, grime, vandalising visitors - and superbugs

Imagine what your house would look like if 3.5 million people walked in and out of it every year. Not only that, but hundreds of thousands of them would arrive sick and infectious. They'd sleep in your beds, and have operations and babies. They'd turn up bleeding all over the place from car crashes, or have cancer or sexually transmitted diseases. Many would be violent, drunk, vomiting, disturbed.

Imagine what your house would look like if 3.5 million people walked in and out of it every year. Not only that, but hundreds of thousands of them would arrive sick and infectious. They'd sleep in your beds, and have operations and babies. They'd turn up bleeding all over the place from car crashes, or have cancer or sexually transmitted diseases. Many would be violent, drunk, vomiting, disturbed.

Then, perhaps even worse, a whole load of their friends and relations would show up to visit them, and tramp through your hallway too. Some of them would spit on your floors, drop fag-ends, take drugs in your lavatory, and vandalise your bathroom. Imagine the state of your place - pigsty, or what? I mean, how would you ever tidy up?

This might be a trite comparison to illustrate the job faced by the cleaners at a big urban hospital - but possibly no more trite than the Conservative Party's electioneering slogan which implies that cleaning a hospital is no more difficult than giving your living room a quick once-over with the Dyson. "I mean, how hard is it to keep a hospital clean?" the posters demand. At St Mary's Hospital in Paddington, everyone - from chief executive Julian Nettel to the cleaner Jesus Ellasos, who's mopping the floor - says that actually, in fact, it's as you've guessed: complicated, relentless, and hard.

St Mary's is one of Britain's biggest and busiest hospitals. Passengers on the buses which grind along Praed Street in west London may glimpse a small plaque on the hospital wall. "Sir Alexander Fleming 1881-1955," it reads, "discovered penicillin in the second storey room above this plaque." Above it towers the colossal Victorian frontage of the Clarence Memorial wing, begun in 1892. Other main buildings date from 1884, 1874, and even from 1845 when St Mary's was founded as a hospital for the poor, relying on charity. Behind the façades, the complex is a mass of ducting, pipework, walkways and temporary-looking buildings, installed as the hospital has struggled to provide a modern service in premises more fit for a museum.

And yet from this ancient rabbit warren of corridors, stairs and cramped rooms, it has produced two Nobel prize-winners; pioneered stroke prevention surgery (and remains one of the top five hospitals in the country for stroke care); remains a world-class centre for teaching and research; has pioneered robotic surgery, and kidney and pancreas transplants for diabetics; and has achieved the highest possible status - three stars - in the NHS performance ratings for the past three years. Perhaps even more amazingly, given its antiquated premises, in the past three years the hospital has also won top ratings for cleanliness.

One of the people who helps achieve this - on £5.50 an hour, 7am-3pm shifts - is Jesus Ellasos, 38, from the Philippines. I feel sorry for him as he shyly struggles with his English, surrounded by us and clipboards and cameras, with his managers and employers in tow, watching to see what he will tell me about his job. Every day on Thistlethwayte Ward - a women's ward - he cleans the lavatories at least twice. He wipes every surface where dust can collect. He sweeps, mops and polishes round each of the 20 beds, which means moving each of them, and their locker and chair and bedside table. He has to do this while visitors trail in and out, and dump their bags or knock over their coffee on to the floor he's just cleaned. If someone's been sick, or messed up the toilets, or there's been some other "spillage", he's called to that too. He's been at St Mary's for seven months.

"Sometimes a lot of people coming in," he says softly, "and a lot of things everywhere, so very difficult to mop the area. Before I was house cleaning but this is very different. Infection is the risk to prevent here." His colleague Isha Conteh, who has been at St Mary's for 16 years, agrees: "This ward is very narrow, so it's hard to mop with so many people around. It's difficult when doctors keep stepping on my wet floors."

In the maternity unit - 3,400 births a year - Mercy Perera is cleaning one of the labour rooms. This includes not only the floor, all the surfaces and the sink, but even the inside of the paper-towel dispenser. "I like cleaning," she smiles, swishing it furiously with her cloth. Originally from India, she's been here 12 years. "Sometimes it's really hard to clean, because of all the patients' property and luggage. And patients, staff and visitors coming in and out - sometimes very rushed to get everything done."

Ellasos, Conteh and Perera work for ISS Mediclean Ltd, part of the Danish ISS group, one of the world's biggest cleaning and facilities multinationals, which operates in 42 countries. ISS has held the cleaning and catering contract at St Mary's and its associated Western Eye Hospital for three years, and the 105 cleaners it employs here have a colossal job. The number of people they have to clean up after is fierce: 259,000 outpatients a year; 96,000 cases in A&E; 41,000 day surgery and inpatients; 32,000 attendances at the sexual-health clinics. Along with miles of corridors, there are 37 wards to be cleaned; 610 beds; 12 operating theatres; eight laboratories; and an unending labyrinth of side-rooms and offices. The hospitals' 3,700 employees include 761 doctors, 1,500 nurses, and some 700 admin staff. The hospital calculates that between staff, patients and visitors arriving every day, the traffic in and out of the buildings is equivalent to 3.5 million people a year.

St Mary's now spends £2.3m annually on cleaning, £600,000 more than in 2000, when it was marked in the "red" category for poor levels of cleanliness. Since ISS won the contract in 2001, this and the extra spending has kept the hospital in the top cleanliness category. The minutiae of the cleaning process is set out in a doorstop folder, hundreds of pages thick, to ensure that ISS meets the hospital's specifications set out in the NHS Healthcare Cleaning Manual.

This devotes three pages and two diagrams to showing how to clean a washbasin. "Equipment required: colour-coded buckets, bottle brush, non-abrasive pad, pair of tweezers, detergent, surface cleaner", it begins, and goes on to detail the removal of "hair or any other items from the plug, plug hole, and plug chain with the tweezers. Start cleaning from the outside and work towards the inside... wipe the surrounding surfaces of the bowl including ledges, pipes underneath the basin, paper towel and soap dispensers... Clean the overflow with a bottle brush. To remove any build-up of soap and grease repeat steps 10 and 11...". All the different areas, from operating theatres to offices, have different levels and specifications for how they should be cleaned.

Every chemical and piece of equipment is detailed. "For example, you cannot have poisonous substances in hospital - so though most people would have it at home, we can't use bleach," says Julie Anderson, ISS's general manager at St Mary's. "Everything has to be regulated, and our domestics have to be aware of what the different chemicals are used for." Anderson's colleague Jacinto Jesus, ISS senior services manager in charge of the day-to-day catering, portering and cleaning operation, says that the ancient buildings make the job harder still.

"The fabric of the older buildings doesn't help when people walk into the hospital," he says. "Because it's old, it gives an impression that it's not clean, even if it is. You find scuff marks on walls, and dents in doors from the trolleys, so it's very difficult. It's partly about perception really."

Anderson agrees. "I think that's our biggest battle," she says. "We know the trust is under-funded, so we have to clean areas where you've got flaking paint - and from the patients' point of view they don't see that it's probably very clean. They just see the flaking paint. It's getting harder to maintain because the fabric's getting older, and expectations are rising all the time."

Once the majority of the ward cleaners leave at 3pm or 4pm, ISS must still have staff available to empty bins, clear up spillages, and clean blocked or messed-up lavatories throughout the night. Most of the corridor cleaning is done at night, the only time when these are not thronged with people.

Both Anderson and Jesus say that, although ISS are contractors, the cleaners are treated as part of the St Mary's team. "Years ago it was a problem to motivate staff, because no one really cared about the cleaners," says Jesus, "but that's changed because cleaning is now so important to hospitals. They really have to appreciate the cleaners - and I think they do."

Anderson says that, far from being the easy task the Conservative posters imply, the cleaning operation is huge, and relentless. "This is our job and we've had years of practice, so perhaps we make it look simple," she says. "But when you start breaking it down into all the separate tasks that you need to do to keep a hospital clean, it's immense. For 24 hours a day, 365 days a year, you've got to keep the pressure on to keep standards up - we cannot, ever, walk away. That's what's difficult - you can't have one bad day."

In wet weather, people tramp dirt and water into the corridors. Some visitors will spit or blow their noses on to the floor in the corridors. Others actually set out to make a mess: take drugs in the public lavatories, flood them, or smash them up. "They don't care - and they damage things on purpose", says Jesus. "Our public toilets get vandalised every day. You go in and find dispensers ripped off the walls, urinals and toilet seats broken - and that is 100 per cent every day, I can assure you."

Up on the 14-bed Almroth Wright HIV ward - which also treats patients with damaged immune systems who might be suffering with anything, from alcohol-related liver damage, hepatitis or liver cancer - ward manager Glenn Holdsworth says that hygiene and cleanliness is even more of a priority. "I've got an excellent cleaner who's been here for about 10 years," he says. "She knows the ward inside out, knows the patients, knows the doctors, and she's part of the team." He says he thinks the Conservative posters are unfair and misleading. "Look at how many people have come in and out of the ward already," he says. "This is a public building, open 24 hours a day - and we can't control who comes in. You may have picked something up in one of the other wards and brought it into my ward. We can't police things like that. I don't think people realise how difficult it is." He believes that the posters - and the media coverage of MRSA - have been playing on people's insecurities. "All the press stories have been about hospitals being filthy, manky places where you'll catch something that will kill you. It's hugely blown up, out of all proportion. MRSA, for example: you very rarely die of it. It's more often the [illness] that you came into hospital with that will kill you, not MRSA. But it's been so sensationalised. It's just not accurate."

St Mary's says that last year it found 28 "hospital-acquired" cases of MRSA (down from 49 in 2003). But, as senior members of the hospital's infection control team explain, the truth behind the bacteria methicillin-resistant Staphylococcus aureus is far from being as simplistic as it has been portrayed. Infection control service manager Gerald Haffenden and consultant microbiologist Dr Marianne Nolan point out that an estimated 30 per cent of normal, healthy adults and children carry a form of the bacteria on their skin or in their nasal passages anyway.

"People are very frightened of it - but you may have MRSA living on your skin or in your nose and be perfectly healthy and well. The majority of people don't get infection from it," says Nolan. "The minority who get an infection are usually susceptible patients, whose immune system is depressed, or who have post-surgery wounds, and they are going to be more vulnerable. But there are good treatments for it, and we would want to reassure people on that."

Meanwhile, though, political campaigning and media stories have indelibly linked MRSA with "dirty hospitals". Nolan says that this link is tenuous, at best. By far the most common method of MRSA transmission is by hand contact. In response, last year St Mary's installed hand-sterilising alcohol-gel dispensers at the entrance to every ward and outpatient department and beside every one of the hospital's 610 beds. This costs £70,000 a year alone.

"It's obviously desirable to have a clean hospital," says Nolan, "but there isn't much evidence to suggest that poor cleaning equals a high rate of MRSA. It's very well known that the main route of transmission is direct contact, usually on the hands of healthcare workers or visitors or whoever else. So it's over simplistic to say that if you just employed loads more cleaners, that would sort the problem. It isn't that simple by any means. But hand hygiene is a very important factor."

Given the 30 per cent level of "normal" Staphylococcus aureus bacteria in the wider community, some of the hospital's visitors will almost certainly carry the MRSA variant, and thus could infect their sick relatives. "Infection control is now everybody's responsibility; and there's huge awareness of its importance among staff," says Haffenden. "One of the challenges for us now is the patients and their relatives - we're trying to encourage them to be careful when they come into the hospital, and to use hand gel when they enter or leave a ward."

In a busy hospital, something that has just been cleaned may remain clean for only a few minutes. Father-and-son team Keith and Andrew Murray are in charge of almost all St Mary's support services, and oversee the ISS cleaning and catering contract. Before one official cleanliness inspection, Keith recalls nipping into a set of lavatories to check they were OK.

"They were wonderful, lovely and clean, smelt nice and everything," he says. "Half-an-hour later we went back with the inspectors. They were flooded, with toilets overflowing where people had stuffed paper towels down them, and water everywhere. They were an absolute mess. So although we're absolutely dedicated to it, keeping a hospital clean is very hard."

He says that even the newest major building on the site, opened in 1988 - the Queen Elizabeth the Queen Mother wing - now needs refurbishment. "If the fabric looks tired and the walls are scraped, the impression is that it's dirty. It may be clean, but psychologically, to the patients and visitors, it's dirty - and that's the problem."

St Mary's chief executive Julian Nettel insists that, despite the difficulties, the hospital cannot compromise on cleanliness. "I think it's perfectly reasonable to expect hospitals to be clean, and to expect the question of cross-infection to be taken extremely seriously - which we do, albeit in difficult circumstances."

So, how hard is it? "When you've got a hospital that is up to 150 years old, and which was designed by the Victorians with a completely different type of health service in mind, and with facilities that are really that outmoded, it is sometimes enormously difficult," he says.

Nettel points out that St Mary's decision to spend an extra £600,000 annually on cleaning was taken in 1999/2000, well before the current political and media furore about "dirty hospitals". Inaccurate MRSA scare stories have, he says, been demoralising for his staff, from cleaners to consultants. And however clean and infection-free St Mary's is kept, the constant arrival of new patients inevitably compromises that. The private sector, he insists, must shoulder some blame.

"There is no doubt that we do see an awful lot of infection in some nursing and residential homes," he says. "What is very difficult and something one has to constantly guard against is that you create a regime where you have a clean environment [here], and that gets literally infected by patients being imported all the time." The only real solutions, he believes, would be either pre-admission screening of all patients, or initial isolation of new arrivals. But the former would be impractical in emergency cases, and the hospital does not have the capacity for the latter.

Plans to demolish and completely rebuild St Mary's, and to incorporate the Royal Brompton and Harefield Hospitals into a new Paddington Health Campus are currently being considered by the Department of Health. Nettel hopes for a decision on this "shortly after the general election". If approved, the project would create one of the largest and most modern healthcare operations in Europe.

Meanwhile, staff must struggle on in their antique surroundings. Keith and Andrew Murray take us up a ramp in a courtyard at the rear of the building, to a sparkling new diabetes and chemotherapy unit which is just being completed - in a converted 1874 stable block which once housed 600 horses for the Great Western Railway. "We'll have the latest, state-of-the-art facilities here - in the old stables," says Keith. "You can see why we're crying out for a new hospital." For the moment, at St Mary's, not just medical and cleaning skills are required. Ingenuity is a prerequisite, too.


* In most developed countries, between 6-10 per cent of people admitted to hospital acquire an infection of some kind. The UK figure is estimated at 9 per cent

* MRSA (methicillin-resistant Staphylococcus aureus) is now a problem in hospitals around the world. Britain has the highest incidence in Europe

* "Normal" Staphylococcus aureus is a common bacteria carried by around 30 per cent of healthy people, to whom it does no harm. Increased use of antibiotics and genetic adaptations in the bacteria produced a penicillin-resistant strain in the 1950s

* In 1960 methicillin was introduced as treatment. The bacteria soon evolved to produce a methicillin-resistant strain: MRSA

* MRSA only causes serious problems if it enters the bloodstream through cuts or wounds - eg during or after surgery. It may cause wounds to turn septic; or toxic shock or blood poisoning. In extreme cases, it can kill

* The National Audit Office says "up to 5,000 people may die" in the UK each year from a range of infections acquired in hospitals

* Mandatory reporting of "hospital-acquired infections" was introduced in 2001

* In 2003-04, there were 7,647 cases of MRSA (up from 7,250 in 2001-02)

* The latest cleanliness inspection figures for hospitals in England found that 118 were "excellent"; 456 "good"; 583 "acceptable"; 24 "poor"; and three "unacceptable"