Britain's museums and galleries generated £1bn in revenue from overseas tourists during 2009, according to VisitBritain estimates.

The figure comes from last year's International Passenger Survey, which included questions charting the activities undertaken by inbound tourists while in the UK.

Of the 30 million inbound visits in 2009, around 7.7 million said they had visited a museum and a further 4.2 million had been to an art gallery during their stay.

The report also shows that, when measured on volume, the French are the most eager visitors to museums with about 960,000 visitors each, closely followed by the Americans, Germans and Spanish.

Although not appearing in the top ten in terms of volume, Brazilians and Argentinians are the most avid museum visitors - nearly two-thirds had made a visit.

The busiest time for foreign visit is July to September, while the period from January to March is the quietest.

The longer the duration of the stay, the more likely a tourist will visit museums and art galleries. While people on a short stay are more unlikely to visit a cultural institution, 42 per cent of people who stay for two weeks or more will spend time at museums.

Sandie Dawe, chief executive, VisitBritain said: "This survey showcases the international appeal of Britain's culture and heritage - where else could you see Grand Masters next to cutting edge installations, a Spitfire hanging next to a Dali?

"Tourism is the golden thread running through the cultural sector, delivering the economic benefits of our world class culture and ensuring that these great works and museums continue to be appreciated."

VisitBritain also published the number of individual visits made to London's most popular museums and galleries.

The British Museum is still the most popular, despite a 6 per cent fall in attendance during 2009, followed by the National Gallery.

Eight out of the 10 most visited attractions in London saw an increase in visits during 2009. Only one paid-for attraction, the Tower of London, features on the list.

The full list of London's top ten most visited heritage attractions:

1. British Museum, 5,569,981 visits during 2009 (-6.1 per cent compared to 2008) 2. The National Gallery, 4,780,030 (+9 per cent)

3. Tate Modern, 4,747,537 (-2 per cent) 4. Natural History Museum, 4,105,106 (+9.8 per cent)

5. Science Museum, 2,793,930 (+3 per cent) 6. Tower of London, 2,389,548 (+11 per cent)

7. National Maritime Museum, 2,367,904 (+15 per cent) 8. Victoria and Albert Museum, 2,269,880 (+10 per cent)

9. National Portrait Gallery, 1,961,843 (+6.4 per cent) 10. St Paul's Cathedral, 1,821,321 (+8 per cent)