Great Britain's athletes will cut a golden swath through the gloom afflicting the City today when they parade their modern record haul of medals in front of thousands of wellwishers in the capital. Recollections of their glorious summer in Beijing must have captured the imaginations of even the flintiest-hearted banker and the ceremony is being partly funded by two City financial institutions.

Lloyds TSB, the troubled bank, has underlined its commitment to its £80 million Olympic sponsorship by helping to foot the bill. The cost for the day is more than £400,000 but four leading sponsors for the London 2012 Games have stepped up to pay most of the bill. As well as Lloyds TSB, Visa, the credit card company, BP and BT have made contributions to try to put a smile back on faces and revive memories of Britain's most successful Olympic performance in a century.

Crowds are expected to line the route, which will take the 500 athletes through the heart of the City. The parade of a dozen floats will travel from Mansion House at 11am, past St Paul's Cathedral and along Fleet Street before arriving in Trafalgar Square by 12.30pm. That will mean widespread traffic disruption as roads are closed and buses diverted. Security will also be rigorous, with 160 officers from the Metropolitan and City of London forces patrolling the route.

This will be the first time that the entire Britain Olympic team of able-bodied and Paralympic athletes have been gathered together, led in the first float by Chris Hoy, the triple gold medal-winner, and the rest of the hugely successful cycling squad.

Rebecca Adlington, the surprise double gold medal-winner, will bring up the rear with the rest of the swimming squad. In between will be a host of familiar faces from Beijing, among them Christine Ohuruogu, who won gold on the track in the 400 metres, and Tom Daley, who reached two diving finals at 14 - though he has had to ask for the day off from school, the Eggbuckland Community College in Plymouth, to attend the celebrations.

This will be the biggest sporting tribute since the England cricket team celebrated overcoming Australia to regain the Ashes in 2005. This time, though, Britain's Olympians and Paralympians will be celebrating beating the rest of the world, with organisers hoping that this is the start of the push towards London 2012.