Leading visitor attractions in London lost out as the double impact of the Olympics and the wettest summer in 100 years caused a calamitous slump in tourism.

The Association of Leading Visitor Attractions said some members saw visitor numbers decrease by more than 21 per cent. The biggest hit was taken by gardens and leisure attractions, where numbers were 21.3 per cent lower between May and August than a year earlier. Visitors to heritage sites, such as the Tower of London and St Paul's Cathedral, also dropped by a fifth.