London’s benchmark index was up 1.2% after opening, while the CAC rose 1.1% in Paris, and the DAX was up by 0.9%.

Johnson will resign as Conservative leader and UK prime minister today, but will remain in the role until the autumn, with a Conservative leadership race to begin this summer. A new leader is set to be in place in time for the Conservative party conference in October.

Amongst the resigning MPs were Secretary of State for Health and Social Care Sajid Javid and Chancellor of the Exchequer Rishi Sunak. Nadhim Zahawi replaced Sunak as chancellor and soon urged Johnson to resign.

On Tuesday, it was confirmed that Johnson had been previously informed about an investigation into the inappropriate conduct of MP Chris Pincher, who he appointed as deputy chief whip.

"You must do the right thing and go now,” Zahawi told Johnson.