Commuters in London received more bad news as it was discovered that using the tube can cost significantly more per mile than a transatlantic business class flight.

The journey from Hillingdon to Baker Street on the Metropolitan line takes less 40 minutes each way and costs £10.20. At a distance of 23 miles for a return journey, you would pay 44p per mile.

By contrast, A return flight from Heathrow to New York on Virgin Atlantic's "upper class" costs £2199.55 which, at a distance of 6904 miles, costs just 33p per mile.

The statistics were released by the Labour London Mayor candidate Sadiq Khan who said TfL fares had gotten "ludicrously expensive under the Tories".

Mr Khan said, if elected, he plans to freeze all TfL fares for four years whilst Conservative candidate Zac Goldsmith has implied he plans to increase fares by 17% in the next four years.

The Labour candidate added: "If Zac Goldsmith gets his way then a Tube journey could end up costing more per mile than taking a private jet around the world."

Mr Goldsmith responded by saying Sadiq Khan's plans will be a "dangerous experiment" and that there are a lot of transport projects which are "slightly more than a wish-list, but they won't happen if the funding is removed.

"My commitment is to protect funding so that these projects will actually happen," he added.