Footfall in Ealing Broadway dropped by 7.4 per cent last week after the Westfield shopping centre opened - but the town centre still fared better than the national average.
Special cameras mounted at head height next to pavements in Ealing Broadway counted people moving past 190,624 times in the week beginning on November 3, down from 205,823 the same time last year.
Similar cameras all round the country recorded an average drop in footfall of 11.8 per cent compared to the same time in 2007.
The busiest time of the week was on Saturday at 4pm, followed by peaks on Sunday at 2pm and Friday at 2pm and 6pm.
The figures have given hope to business leaders, who had feared a much bigger impact from the combined effect of the economic downturn and the opening of the new mega-mall.
But while initial numbers suggest Ealing may have done better than expected, a collective drop in takings of £40m is predicted as a result of Westfield's launch.
Early signs show the drop-off in Ealing's footfall is accelerating at a similar rate to elsewhere. In the previous week - starting on October 27, four days before Westfield opened - the cameras were passed about 203,000 times, down from 214,000 the same time last year and a fall of 5.2 per cent. Nationally, the average drop was around 7.8 per cent.
Steve Breen, executive director of Ealing Broadway BID, said: "We have experienced a fall but it hasn't been as extreme as has happened in other places around the country.
"In terms of the number of people on the street and going into the shops, Ealing is still fairly busy.
"We haven't been completely abandoned, but there's no room for complacency. A drop of 7.4 per cent is significant in its own right.
"We're targeting Christmas to try to address that, and our approach is a combination of putting in an even bigger ice rink and pushing the message about shopping locally."
Matthew Sims, of Ealing Chamber of Commerce, said it was too early to comment on the impact of Westfield, but added: "What Ealing has to do is recognise what Westfield has done, and to take that proactive direction and regenerate Ealing in line with what they've done in Shepherd's Bush."
