Economists said a reduction in windfall spending in July to pounds 100m from June's pounds 200m showed the consumer boom was flagging as quickly as it blew up in the first half of the year.
They believe further cash may trickle into the shops through the autumn, but say the apparent need to jack up interest rates to dampen demand is now less urgent.
Clive Vaughan, at the retail consultant Verdict, said: "The surge that came through, particularly in June, does seem to be a bit calmer now. But we could still see some windfall spending filtering through until the beginning of next year."
The latest retail sales data showed growth up 0.3 per cent in July after a 0.8 per cent rise in May and a 1.2 per cent increase in May.
Analysts attributed the surge in retail sales in May and June to higher spending financed by windfall cash, which mostly went on large household items.
A survey of households conducted by consumer research group Mintel and investment bank Robert Fleming and published this week concluded that less than 25 per cent of the windfall cash had been, or would be, spent with nearly 77 per cent saved or used to repay debt. That would amount to pounds 8.2bn of extra spending power this year.
Peter Warburton, economic adviser at Robert Fleming Securities, said the latest figures chimed with his firm's survey, which was published earlier in the week: The surge in consumer confidence, which has occurred during the past six months as these windfall payments have been eagerly awaited, is likely to be reversed quite rapidly this autumn."
Mr Vaughan said there was little evidence the large payouts had permanently affected consumers' spending habits.