Shopper numbers were down 2.6 per cent between July 10 and July 16, compared with the previous week. But footfall was flat compared with the same week last year.
FootFall spokeswoman Natasha Burton said: 'Necessity shopping is still taking place, but other leisure activities and trips tend to fill the gap previously occupied by shopping.'
However, some retailers have been benefiting from the prolonged spell of hot weather, with sales of fans, air-conditioning units and summer food and drink all reported to be increasing.
According to FootFall, the start of the school holidays next week should help drive footfall as preparations for holidays abroad and in the UK begin.