Mobile phone networks have been asked to cut off pimps and prostitutes ahead of the 2012 Olympic Games.
City Hall bosses called on top phone companies, including Vodafone, 02, 3, Virgin and T-Mobile, to help crack down on prostitution and trafficking in the lead up to the sporting extravaganza.
They want help targeting numbers advertised on thousands of sex calling cards that litter phone boxes throughout the capital.
Kit Malthouse, deputy mayor for policing, said the mobile phone numbers are a valuable resource for those behind the sex industry.
He said an agreement must be reached between mobile phone networks and police that sees them taken out of use as soon as they are identified.
Mr Malthouse said: "If you are an American tourist and you walk into a telephone box you would think it was a sex shop.
"We want a streamlined, agreed process for barring these numbers because they become very valuable for a number of reasons. Firstly, they become a source of repeat business. Plus the numbers operate as a kind of switchboard, there will be several poor girls operating behind the number.
"Hopefully it will become dangerous to advertise your number in these boxes because you may lose your business.
"If you are a trafficker or pimp all you are interested in is money, you are certainly not interested in the welfare of the women or young girls."
Chief executives of all the major mobile operators have been invited to a meeting at City Hall in October.
