Top Four

1. Norwich 2. Colchester 3. Chelmsford 4. Cardiff

The supermarket chain sells 10% more Viagra in Norwich than anywhere else in the UK.

Norwich Chamber of Commerce spokesman Lyndon Green said the city's elevated standing in the Viagra league was "probably a sign of the fact that Norwich is such a buoyant and great place to live that people are looking at enhancing their lifestyles even more".

Sir Malcolm Bradbury, professor of American Studies at the University of East Anglia, said: "It just shows what a creative place Norwich is.

"I'm surprised, but there may be a demographic reason for it - Norwich attracts a lot of people who are moving towards retirement and are maybe looking to revive their lives a bit, looking for a bit of pleasure.

"It has been going through a fairly big cultural change over the last few years and it is actually getting a younger and more varied population."

However, a spokeswoman for Norfolk Health Authority was unable to say why the city was top of league.

"We can't really pinpoint a reason why Norwich came so far up the table."

Norwich was followed by Colchester, and Chelmsford in Essex and Cardiff in Wales.

The lowest sales figures for Viagra were recorded in Haverfordwest in South Wales, which sold 70% less of the drug than stores in Norwich.

Other towns at the bottom of the list were Hartlepool, Hanley, Henley-on-Thames and Hammersmith in London.

Sales of Viagra in England are far higher than anywhere else in the UK - but the company acknowledges that this is because it has many more stores there.

Bottom Four

1. Haverfordwest 2. Edinburgh 3. Hammersmith 4. Henley on Thames

However, Tesco's figures show that Scots are less likely to buy Viagra. Customers in Inverness bought 40% less of the drug than those in Norwich and customers in Edinburgh bought 68% less.

Nicki Harvey, Tesco health and beauty spokeswoman, said demand for Viagra was growing all the time.

"Viagra is becoming increasingly popular now that the novelty has worn off.

"Our pharmacies have reported that customers are very open about buying it whereas even a year ago they might have waited for a quiet moment before asking."