Mayor of London Boris Johnson has apparently signalled his support for an extension of the Bakerloo line beyond Elephant & Castle.
Southwark Council leader Peter John – whose petition in favour of a tube extension to Camberwell and Peckham has gained more than 2,000 signatures – says that he extracted the commitment from the Mayor during a controversial visit to a property trade fair in Cannes.
The Labour council leader tweeted that Mr Johnson had replied "It's a deal" when asked to support the Bakerloo line extension.
Cllr Peter John said: "The response to the petition has been phenomenal. It shows the strength of feeling there is in Camberwell and Peckham about the need for improved transport links.
"People have talked and talked about extending the Bakerloo line for decades, now Boris has a chance to deliver a lasting legacy for South London. I am delighted he has given a verbal commitment to me to deliver this project, now he has to put his money where his mouth is and deliver the Bakerloo line to Camberwell and Peckham."
Last week the Mayor indicated tentative support for the project at a People's Question Time event in Catford, despite advice from Transport for London officials that the sums don't add up.
"They have told me before that they do not think there is yet a good enough business case, and you can do more good by extending the trains on the overground service," said the Mayor.
"My hunch is that the extension of the Bakerloo line will come and it will be immensely beneficial."
Also speaking at People's Question Time, Lib Dem London Assembly member Caroline Pidgeon said: "I absolutely support the Bakerloo line extension.
"If you look at the map of London and see where all the investment is going – you've got Crossrail, Crossrail 2, Thameslink – South East London is once again the cinderella.
"We're not getting the services we need and it is absolutely right that we get the Bakerloo line extension.
"The business case ... is there and we need the boroughs in this area working together cross-party to put that case to the Government and to the Mayor so we get the funding for this vital extension that is so desperately needed."
The Green Party's Darren Johnson AM agreed that a Bakerloo line extension should be an "absolute priority" for Transport for London.
However, Conservative assembly member Roger Evans warned that any Bakerloo line extension to south east London would be "some way off down the tracks" after the proposed Crossrail 2 line linking north east and south west London.