Special 'swim lanes' are to be created in the River Thames for fit commuters following the success of the capital's 'Boris bikes', it was revealed today.

A Transport for London insider said dredging would begin next week to ensure the lanes were open in time for the summer.

Each lane will be roped off to prevent pleasure boats and debris floating in front of swimmers, a spokesman said.

Sprinkler systems will operate during peak hours to keep the water clean.

The first lane to open will run from Putney Bridge to Westminster, a distance of around 10km. Swimmers will be charged a non-refundable deposit of £1.50 for towel hire.

"The success of London's cycle hire scheme shows the appetite we have for finding healthy alternatives to public transport when travelling to and from work,'' the TfL insider told This is Local London.

"Swimming to work is the next logical step."

Mayor of London and keen swimmer Boris Johnson was unavailable for comment.