The number of shoppers visiting central London has fallen by a fifth following Thursday's failed bombings.
Shoppers continued to flock to Oxford Street at the weekend
Retail tracking agency SPSL found numbers were down 19.1% on Friday and 21.9% on Saturday, compared with the same dates last year.
The second wave of attacks destroyed the idea that the 7 July bombings were a one-off, said spokesman Tim Denison.
Would-be bombers targeted the transport network on Thursday, two weeks after suicide bombers killed 52 people.
Tube stations shut
High street sales inside central London's congestion charge zone had dropped by 10.1% after the 21 July bombings, SPSL found.
Shopper numbers were down 26.9% on Thursday, the day of the failed attacks which again shut sections of the Tube network and some roads.
But SPSL suggests the fact London had been targeted again may mean normal shopping patterns take longer to recover, because people think more attacks may follow.
"It seemed likely that London-based shoppers had mentally filed the attacks as a 'one-off', whilst day trippers and tourists were perhaps more wary," said Mr Denison.
"What is becoming clear now is that shoppers cannot so easily justify shopping if there is the danger of further attacks."
Oxford Street appeared busy on Saturday, although staff at some department stores thought numbers were slightly down.
Annie Walker, for trading association New West End Company, said: "I think the British public is very resilient. They have shown tremendous support for the West End."
"It is the sales so it is busy at this time of year. I am just amazed at how people have still gone to work. I think everyone is saying: 'We're going to beat this'."
Among shoppers on Saturday was Adrian Koba, 28, a consultant from St. Albans.
"People now are just more careful but it doesn't mean that they won't go out and buy some clothes," he said.
"It is different when you come to King's Cross, you see pictures and flowers there but not in Oxford Street, people are out buying clothes just like normal."