Transport minister Stephen Hammond has given a commitment in the House of Commons to discuss the potential extension of the Bakerloo Line beyond Elephant & Castle with Mayor of London Boris Johnson.
More than 2,000 people have signed a petition started by Southwark Council leader Peter John urging Mayor of London Boris Johnson to consider an extension of the Bakerloo line to Camberwell and Peckham.
Nearly 70 people have signed an alternative petition calling for a wider debate on the respective merits of extending the Bakerloo line east via Bricklayers Arms rather than south along the line of the Walworth Road.
Now the Bakerloo line extension campaign has reached the House of Commons.
"For my constituents, one of the most important issues in public transport is extension of the Bakerloo line from Elephant & Castle, where it currently stops, through Southwark to Lewisham and then to join the Hayes line," said Lewisham East Labour MP Heidi Alexander in a Westminster Hall debate on Tuesday.
"That would provide huge benefits in relieving congestion on existing transport routes to London, and would support growth in south-east London and Canary Wharf."
She added: "Overcrowding on overland trains to London Bridge and Cannon Street is unbearable for my constituents. I regularly take the train to London Bridge and it is unpleasant to be stuck in the armpit of a stranger.
"Overcrowding during the rush hour is intense and there is a desperate need to relieve that congestion. The benefit of bringing the tube network to south-east London would be felt not just in people's quality of life, but in the planned regeneration projects in south-east London.
Ms Alexander continued: "Southwark and Lewisham are two of the fastest growing boroughs in London, and it is projected that by 2030 Lewisham's population will be 346,000, which is 70,000 more than at the moment. The rise in Southwark's population will be similar.
"We have a terrifically young population who want to access job opportunities in central London. Those huge population increases in south-east London mean that we must find a way to transport people around."
Transport minister Stephen Hammond told Ms Alexander: "I hear her points about the Bakerloo line.
"I say to her again that, as she will recognise, transport in London is a devolved issue, and it would be for the Mayor to come forward with proposals to the Government.
"Any proposal for London Underground to extend the Bakerloo line further in south-east London is a matter for the Mayor and TfL.
"They would have to come up with a plan, and potentially, if they seek to fund it in sponsorship with the Department [for Transport], come to the department. It is not for the department to impose the proposal on TfL or the Mayor."
Pressed again by the Lewisham East MP, the minister added: "Whenever I meet the Mayor, I discuss many things with him. I promise that when I next meet him – in one of our regular meetings – I will make sure that that is on the agenda."
Last week Mr Hammond's boss – transport secretary Patrick McLoughlin – told Parliament that the proposed Bakerloo line extension is "being looked at closely by Boris Johnson, Transport for London and the Greater London Authority".