An estimated £400m left unused on Oyster cards should be given to the homeless, according to the Liberal Democrats’ London 2020 mayoral candidate.

Transport for London (TfL) released a report last week showing that £400m was left unused on Oyster cards.

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Liberal Democrat mayoral hopeful Siobhan Benita said tonight it should be possible for individuals to hand back the cards to TfL and for the leftover money to be donated to charity.

She branded it as the “#OystersForChristmas campaign” and urged mayor of London Sadiq Khan to adopt the policy ida.

“As we enter the harshest weeks of winter, we’re sure the ever-generous public will want to do their bit to raise what is potentially millions of pounds to help homeless people this Christmas,” she said.

“I’m calling on the current Mayor to help us release that money.”

TfL’s chief technology officer Shashi Verma noted that people could already donate old Oyster cards to support charity.

“Over the last decade, this has helped raise more than £218K for the Railway Children, an international children’s charity who work with street children in India, East Africa and the UK,” he said.

Benita’s policy proposal comes as a part of a package of measures to combat homelessness.

She is proposing to create a City Hall unit that is solely responsible for reducing the rate of rough sleepers in London.

“The new unit would work closely with councils and front line service providers to make it much easier for people to get the support they need,” she said.

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Data from the Greater London Authority shows that rough sleepers in the capital rose by 50 per cent in the year to September.

This was touted as the largest ever annual increase.