More Republicans are quitting Congress than at any time in the last 44 years, analysis for The Telegraph has revealed, as a backlash against Donald Trump gathers pace.

Thirty seven Republicans in the US House of Representatives are not seeking re-election in the 2018 mid-terms – a higher number than any point since 1974.

Fear of being swept away by a “blue wave” of Democratic support is partly driving the exodus, according to experts and Republican insiders.

The trend makes it easier for the Democrats to take back control of the House from the Republicans because incumbent candidates are harder to defeat.

Losing the House would have a profound effect on Mr Trump’s ability to pass new laws in the final two years of his first term and opens the door on possible impeachment proceedings.