Driverless Tube trains will not be introduced for at least another 14 years and are unlikely to be in operation until 2030, according to an internal Transport for London document seen by the Standard.

Train drivers’ unions have seized on the timeline, saying it exposes the mayor’s pledge to introduce driverless trains as empty rhetoric.

TfL is due to place a multi-billion-pound order for new trains after the election in a £10bn upgrade to several lines, starting on the Piccadilly line whose stock was built in 1972.

The Standard understands that TfL has hired London design firm Priestman Goode, which created the look of Virgin’s Pendolino trains, to create a blueprint for the new Tube.

It had been assumed that driverless trains, which are commonplace on the Paris Metro, would be in operation in the early 2020s.

But a “New Tube for London” paper circulated to London Underground managers says it would be nearer the end of the next decade.

It states: “When the New Tube first enters service on the Piccadilly line, it will have a train operator on board, and this will continue until the old fleet is replaced.

“This will take many years roughly to c2025. Any decision on fuller automation would come into effect after this date and in all reality several years after that.”

The document acknowledges that driverless trains are a “key area of concern” and insists that an “operator” would be on board initially.

Aslef, which has 60% of Tube drivers as members, has promised “all-out war” over driverless trains. The RMT, which accounts for the remaining 40%, is opposed on the grounds of safety.

Finn Brennan, district organiser for Aslef, said: “This demonstrates that despite Boris Johnson’s bluster, driverless trains are a myth for the foreseeable future.”

“Even under the most optimistic proposals, it would be at least another 14 years before new trains on the Piccadilly line could be operated automatically.

“Aslef would never accept driverless trains. We are glad that at last LUL is admitting that new trains will be introduced with drivers”

The mayor - a bitter opponent of the unions - has tried to “tame” them with the threat of driverless trains and a call for a minimum 50% turnout before a strike ballot is valid.

Under one scenario, the train could be built with a driver’s cab which could later be removed, creating extra space for passengers.