The proposed extension of the Bakerloo Line cannot be guaranteed as Transport for London reels from the financial pressure heaped upon it by the coronavirus pandemic, a letter from Sadiq Khan's Deputy Mayor for Transport has revealed.

The details come after Greenwich councillor and London Assembly candidate Charlie Davis lobbied for an answer on the future of the project, following last month’s £1.69 billion Government bailout of TfL.

The bailout – which came after TfL’s fare income over the last two months plummeted by 90 per cent – led to widespread media reports the planned extension of the Bakerloo Line from Elephant and Castle to Lewisham could be scrapped.

While deputy mayor for transport Heidi Alexander said she could “categorically assure” Cllr Davis the Bakerloo extension did not feature in any of her discussions on the funding settlement, she acknowledged ongoing pressure on TfL finances meant the future of such projects couldn’t be guaranteed.

“You will be aware however that there is still considerable uncertainty over TfL’s longer term funding arrangements and so just as there was not a confirmed funding and financing package for the (extension) prior to the onset of the pandemic, there is equally not one in place now,” she said.

She added the project is at an early stage of development and work was underway with the Government to safeguard the route extension, saying she would “like to accelerate those discussions at an appropriate time”.

In her letter to Cllr Davis, the deputy mayor also detailed the “catastrophic impact” of Covid-19 in TfL’s finances, adding that London is the only major city in Western Europe that does not receive a Government grant for day-to-day operations, meaning it relies heavily on fares income.

The financial management of TfL has been a bone of contention since the bailout was secured – with Labour and the Conservatives clashing over the issue repeatedly.

Commenting on the response, Cllr Davis, who is running for the London Assembly seat of Greenwich and Lewisham, took aim at what he called “the poor financial management of the Labour administration at City Hall”.

“Even now, the Mayor refuses to take responsibility for this issue and provide the leadership required to guide TfL through this challenging period,” he said.

“The Bakerloo Line extension is a vital piece of local transport infrastructure, not just for Lewisham but for wider south-east London.

This Is Local London: The proposed route of the extension and (inset) London Assembly candidate and Councillor Charlie Davis. The proposed route of the extension and (inset) London Assembly candidate and Councillor Charlie Davis.

“The fact the Deputy Mayor is unable to guarantee the future funding of this project is deeply worrying, I will continue to campaign to ensure this vital project is not sacrificed to bailout Labour’s failings in London.”

In her letter, Ms Alexander said the Government bailout would allow TfL to run public transport safely in London for the next four and a half months, but had left the body saddled with extra debt.

“However, it was not the deal we wanted and will mean TfL taking on an additional half a billion pounds of debt, undoing the hard work the Mayor has put into fixing TfL’s finances over the last four years,” Ms Alexander said.

Future plans published on the Bakerloo extension could also see the tube line extended to Hayes, in a move that has repeatedly been rejected by Bromley Council.

The authority has instead argued for additional capacity and connectivity for existing services in the town centre instead of the tube extension.