An NHS worker was confirmed today as Britain's first case of swine flu being transferred within the UK.
Graeme Pacitti, 24, tested positive for the virus after coming into contact with football team-mate Iain Askham, who fell ill after his honeymoon in Mexico.
Mr Askham and his new wife Dawn, from Polmont, near Falkirk, were released from hospital yesterday after spending five nights in isolation.
The positive test result was confirmed by the Scottish Government.
It comes as a further case of the virus was confirmed by the Department of Health in the North West of England.
A spokesman for the Health Protection Agency said the new case was a woman from the Merseyside who recently returned from Mexico.
She was at home and feeling well and she and her family have been given anti-viral medication, he said.
The total number of people confirmed in the UK as having swine flu is now 11.
Mr Pacitti, who works as a clerical assistant for the NHS, said he was "gutted" and "disappointed" on hearing that he tested positive.
He met friend Mr Askham last Thursday and began to show symptoms on Saturday.
Mr Pacitti has been at his Falkirk flat since he was contacted by a doctor and tested.
He said, just minutes after hearing the results: "I'm gutted really. I just found out.
"I saw Iain last Thursday, he wasn't showing any symptoms then. My friends thought he looked a bit tired but we thought it was just jet-lag.
"I've been feeling a lot better today than I have all week. I've still got an upset stomach and a sore throat. Earlier in the week I was having headaches and feeling feverish."
Confirmation of the first human-to-human case came minutes after the Scottish Health Secretary Nicola Sturgeon said there were technical problems with the tests that were delaying the results.
Mr Pacitti was initially cleared but continued to show symptoms and further tests confirmed he was suffering from Type A flu.
Mr Pacitti said: "Part of me expected the positive result as it would have been a big coincidence.
"It was Saturday night that I started to feel unwell but I wasn't aware that Iain and Dawn had been taken to hospital.
"I got a phonecall from a doctor on Sunday to say that they had been taken in and they had to come out and do some tests because I had been in contact with them.
"I haven't had a chance to speak to them (the Askhams) yet as I can imagine their lives are pretty hectic. Mine certainly is now as well. I will get a chance to speak to them."
Earlier today Gordon Brown urged people with swine flu symptoms to seek advice as he offered reassurance that Britain was well-placed to deal with the outbreak.
On a visit to an NHS Direct call centre in Beckenham, south east London, the Prime Minister said the advice line was coping well with demand.
He said the Government was increasing the number of face masks available to the NHS and looking at different vaccines, while stressing that the Tamiflu anti-viral drug would deal with the bug.
Mr Brown added: "This is happening in every country of the world, but we are better prepared.
"If people have the symptoms they should ask for advice as quickly as possible.
"And we are finding with NHS Direct that they can both reassure people and give people advice about where to go.
"This is a system that's working, it's calm, it's ordered, it's giving people the right information."
Mr Brown said all the cases in the UK were mild.
A Department of Health spokesman said: "The preparations we have in place and are continuing to make will help to ensure we respond well in the event of a pandemic.
"Everyone needs to play their part to protect and prepare themselves and their families. There are simple steps that everyone can take to help prevent catching colds and flu based on good respiratory and hand hygiene.
"Always use a tissue to catch your sneezes, throw away used tissues where germs can linger and regularly wash your hands."
Dr Alan McNally, senior lecturer and influenza diagnostics researcher at Nottingham Trent University, said human-to-human transmission within the UK would not be a significant development.
He said the vast majority of the UK's possible cases currently being investigated are likely to have originated from contact with other infected people.
One of the latest confirmed cases was a woman who recently returned from Cancun, Mexico, and lives with two Newcastle University students.
The two students, who live off-campus and share a house with the infected woman, whose symptoms are mild, have been given anti-viral drugs.
Staff at Procter & Gamble on the Cobalt Business Park in North Tyneside where the woman works were also being monitored although she was only in the office a short time after returning from holiday.
Meanwhile Downend School in South Gloucestershire near Bristol closed this afternoon because of a suspected case of swine flu in a Year Seven girl.
A Health Protection Agency spokesman confirmed it was investigating and the girl was undergoing tests. Pupils who came into contact with her were also being checked for symptoms, the spokesman said.
The World Health Organisation has raised the alert level to phase five of six, meaning a global outbreak is imminent.
Holland and Switzerland both confirmed their first cases of swine flu today, bringing the total number of countries affected around the world to 11.
There have been 248 deaths in Mexico, with 12 confirmed as due to the virus.
The other countries affected are the United States, Canada, New Zealand, Germany, Spain, Israel and Austria.
The Welsh Assembly Government said 16 possible cases of swine flu had been ruled out. Another 20 patients, all with mild symptoms and travel links to Mexico or the US, were being investigated.