Fare evasion on “Boris Buses” cost Transport for London (TfL) £3.6 million last year, the Local Democracy Service can reveal.

The rate of fare dodging on New Routemaster buses is now more than double the bus network as a whole.

Boris Johnson’s Routemasters date from his time as London Mayor – modelled on traditional London buses, they allow passengers to tap in at any of three entrances.

But critics of the new Prime Minister say the problem only adds to the “headache” caused by his fixation on nostalgic design.

TfL is now trialling single-door entry, which will see customers tap in at the front door only, as on other buses.

The new system will start on the route 8 and N8 service from Bow Church to Tottenham Court Road this Friday. If successful it will be extended to all New Routemaster buses in future.

“Boris Buses” make up 11 percent of the bus network, with 1,000 of the 9,000-strong bus fleet now his design.

But they caused a disproportionate four percent of revenue loss on TfL services in 2017/18 – including Tube, Overground and other rail services.

The Prime Minister’s buses previously faced criticism when the lack of air-conditioning or opening windows subjected passengers to sweltering temperatures of 30°C and higher.

TfL has since retrofitted opening windows, at a cost of £2 million.

Labour’s City Hall transport spokesperson, Florence Eshalomi, said fare evasion on the Routemaster revealed Mr Johnson’s skewed priorities as Mayor of London.

She said: “You had the new Prime Minister when he was Mayor prevaricating about bringing back old-style buses, but he didn’t want to clamp down on evasion – and now we have a problem.”

She added: “This is another layer of problems that we’ve been lumbered with by Boris Johnson – it’s just another thing adding to the headache. It’s one thing after another.”

Liberal Democrat assembly member Caroline Pidgeon said TfL was right to tackle fare evasion, but single-door entry “undermines the very point” of the Routemaster design.

She said: “Fare evasion must be tackled, but instead of the vast majority of honest passengers being penalised with slower and more inconvenient journeys I would like to have seen TfL consider stronger penalties for fare evasion and greater use of revenue protection officers.”

A TfL spokesperson confirmed the changes to the route 8 bus, and said wheelchair users would still be able to enter through the centre doors.