Theresa May will face a “stalking horse” challenge to topple her as Prime Minister if she waters down Brexit, senior Tories have warned.

Leading Eurosceptic MPs have told The Telegraph they are prepared to mount an immediate leadership challenge if Mrs May deviates from her original plan.

The revelation comes after a torrid week for the Prime Minister in which she faced fierce criticism for her handling of the Grenfell Tower catastrophe.

Conservative MPs – including Cabinet ministers – have concluded that Mrs May cannot lead them into the next election and they are now discussing when she could go.

Eurosceptic MPs have warned that any attempt to keep Britain in the customs union and single market or any leeway for the European Court of Justice to retain an oversight function will trigger an “overnight” coup.