The team of judges have their work cut out, but, says Richard Chisnell of the BTA, this year the stakes are particularly high - the public lavatory, he warns, is under threat. "There are some wonderful toilets around, but they are few and far between," said Mr Chisnell. "Many are very basic. Coupled with the misuse of public lavatories that is endemic at the moment, there is a real crisis under way."
Britain, explains Mr Chisnell, has lost around 25 per cent of its public conveniences over the past three years, from around 10,000 to 7,500. Only 10 per cent have baby-changing facilities and just half provide access for wheelchairs.
There is no statutory obligation for local authorities to provide public lavatories, and they are expensive to maintain, especially if they have attendants. Mr Chisnell believes that attendants are an endangered species - he estimates that today less than 10 per cent of public toilets are manned.
The added costs of dealing with vandalism and graffiti, plus the unsavoury reputation of lavatories as places to take drugs or go "cottaging", mean it is understandable that local councils throw up their hands and say: "We can't cope. Let's shut it down." Among councils who have closed public toilets are Islington and Camden in central London.
The awards will be handed out in November. Meanwhile, the BTA is mounting a spirited campaign, not only to preserve the lavatories that remain but to open more. "We want the public to demand their toilets back," said Mr Chisnell. "A society gets the toilets it will accept, and the time has come to stir things up and make a fuss."
The group has already had a pro-lavatory motion tabled in Parliament, which garnered the support of more than 100 MPs.
But some lavatories have been lost forever. Often, public toilets are situated in prime sites, and rather than simply close them and let them stand empty, many councils are letting them out or selling them off.
Among the many uses for these ex-toilets are a lawyers' office in Glasgow and an Indian takeaway in Doncaster, while on Shepherd's Bush Green the former lavatory has become a snooker hall. A mason in Glasgow is to rent a former toilet conveniently placed next to the cemetery. Other shining examples include the public lavatories at Osmotherly, North Yorkshire, reputed to be the cleanest in the country.
Open a business in an old loo and there are bound to be some sniggers, so let's get all the hoary old jokes over at once. No, these premises are not bog-standard. Yes, they are all the epitome of convenience. All the owners are flushed with success. And there really is no chance of any of the enterprises going down the pan.
But it takes a keen entrepreneurial eye to spot the potential of what may be a building in a sorry state of repair. Lawrence Delaney, a Belfast businessman, could easily have overlooked the old lavatories in Shaftesbury Square. When he first saw them, the subterranean toilets were flooded and a lorry had partly knocked in the roof.
Mr Delaney was undaunted. He plans to open a restaurant and bar on the site. "I like unusual buildings, something a bit different to the norm," he said. "It's an excellent location."
The shape of the building, he says, resembles the stern of a boat, so he is planning a refit along nautical lines. "We'll have wooden decking, the customers will be passengers and the staff will be dressed as stewards," he said. He is pondering asking his guests to turn up in lifejackets for the opening night.
Dennis Neale, a part-time social worker, has made one of the most unusual conversions. He is currently finishing work on the Theatre of Small Convenience in Malvern. "It used to be a tiny, Victorian gentlemen's loo," he said. "I thought it would make a wonderful little theatre. It's very intimate inside."
The theatre will seat 12 people and a play has already been written for performance on the 4ft-wide stage. Curiously, due to space constraints, there is no toilet in the theatre - the nearest one is across the road.
Most conversions tend to start by pulling out the original facilities, but Heartland FM radio station in Pitlochry hopes to retain its chosen building's original function. The radio station is currently fund-raising to secure a toilet block big enough to serve both as a convenience and a broadcasting centre.
Mr Chisnell would approve of Heartland's stance. He points out that unusual old lavatories, sensitively restored, can become tourist attractions in their own right. The Victorian-built gentlemen's toilet fitted out in green marble, glass and copper, is a magnet for visitors to Rothesay pier. It has been described by architectural historian and lavatory aficionado Lucinda Lambton as "the jewel in the sanitarian's crown".
Mr Chisnell also has a vision of the toilet of the 21st century. "With some imagination, public toilets could become complete comfort stations, offering showers, massage and all kinds of services. It just needs someone like Richard Branson to take up the vision," he said.
n Do you know of a convenience under threat in your area? Write, sending a photo, to Best Loos, The Independent on Sunday, 1 Canada Square, London E14 5DL.