The expansion will add more than 2,000 bicycles and around 250 new docking stations to the scheme which will now serve parts of Wandsworth, Hammersmith & Fulham, Lambeth and Kensington & Chelsea.
It is due to open in December and follows completion of an eastern expansion last year.
When completed, Mayor Boris Johnson says the scheme’s new phase will “be a real benefit to local people” and support his ambition to make cycling “an integral part of the capital’s transport network”.
The Mayor recently announced a major new cycling strategy, including plans for a network of “high-quality” cycle routes across the capital.
Despite privately telling them that expansion into their areas was “dependent” on them providing funding, Transport for London has proven reluctant to publicly acknowledge the boroughs’ contribution.
The capital’s transport authority, which is chaired by the Mayor, has previously denied its agreement with Barclays prohibits acknowledging other funding partners. Despite the claim, TfL’s statement announcing the commencement of construction works omits any mention of funding partners other than the bank.
When upfront construction costs are factored in, the losses could be as high as £180m.
TfL’s own figures show that 93 per cent of all journeys made scheme members last less than 30 minutes, meaning “the vast majority of people using the scheme aren’t paying any more than their access fees”.
The lack of longer journeys, for which members have to pay additional usage fees, is a key factor in the scheme’s failure to break even.
In addition to seeking cash from Boroughs, TfL and the Mayor have been forced to double the scheme’s membership fees in order to stem its losses. The Mayor has said the increase will raise an additional £6m per year.
Last month the number of bikes hired fell to the lowest level in more than a year, with just 504,611 hires compared to 818,209 in March 2012.
TfL’s Nick Aldworth says the new south-western phase “will help create thousands of additional journeys each month”.