British officials are in discussions with Brussels about extending the Brexit transition period to almost three years, The Telegraph has learnt.

The official Government target for transition is “around two years” but many senior Whitehall officials remain privately concerned about the practicality of such a short transition, given potentially massive changes that would be required by a “hard” Brexit.

The Telegraph understands that although it is not formally Government policy, Britain has discreetly begun sounding out senior EU figures over whether transition could be extended amid growing disarray within the Cabinet over the ultimate terms of a long-term deal with the EU.

Theresa May has faced a series of challenges from senior Government figures in recent days and is braced for another testy Cabinet session on Monday over the Brexit strategy with some Conservative MPs demanding that the Chancellor, Philip Hammond, is moved.

Any push to extend the transition period is likely to lead to a fierce backlash from Conservative Brexiteers, already concerned that Britain risks becoming a "vassal state" during transition.