Two key West London bus routes have been saved after being backed in a petition signed by more than 4,000 people. Mayor of London Sadiq Khan announced on Wednesday that routes 14 and 74 from Putney to Russell Square and Baker Street respectively will not be cut following local outrage.

Transport for London (TfL) proposed major changes to the capital's bus routes after being told by the government to find savings. The authority planned to remove 16 routes and change 77.

But only three bus routes will be scrapped instead – routes 332, 507 and 521 – and 18 will be changed after Mr Khan allocated an extra £25m in funding to TfL per year. Routes 14 and 74 will be kept as they currently operate.

A petition to save the routes signed by more than 4,000 people calls them an "important lifeline" for residents, particularly elderly and disabled people, as they pass three major hospitals – Royal Brompton Hospital, Chelsea and Westminster Hospital and Cromwell Hospital.

It adds that the routes are key for people travelling from South West London to the West End. Unite the Union members, who work as bus drivers, were joined by residents and Putney MP Fleur Anderson at protests against the changes earlier this year.

Ms Anderson said she is "over the moon" the 14 and 74 routes will not be cut. The Labour MP said: "This is wonderful news for our elderly and disabled, for our environment, and for all of us who believe that more affordable, accessible, greener transport is the future for Putney.

"I led two local protests, and one outside Parliament, met with the mayor and deputy mayor for transport to make the clear case for why we needed the routes. I raised accessibility to healthcare, as the routes serve hospitals, passenger safety and made clear that Putney wants more affordable, environmentally conscious ways to travel – not less."

Mr Khan said: "I was furious on behalf of Londoners that TfL was having to consider reducing the bus network due to conditions attached by the government to the funding deal. The strength of feeling across the capital was clear to me, and I was adamant that I would explore every avenue available to me to save as many buses as possible.

"This will mean tough decisions elsewhere, but I am very pleased that the vast majority of bus routes proposed to be cut due to the government's funding conditions can now be saved."