In a letter to The Times, the group of 21 academics from leading universities and research institutions, including Oxford, Cambridge, Edinburgh and UCL, said the prorogation is “far from normal”.

The suspension of Parliament would be “the longest since 1930”, they warned, and is “clearly designed to evade scrutiny, including legislation, and even a potential no-confidence vote”, which “sits badly with the core principle in our democracy of government accountability to parliament”.

It ends: “The UK constitution depends not just on law but on conventions and precedents. If key players reject the accepted norms they undermine the integrity of the system. This sets dangerous precedents, both for the UK and other countries that look to us for democratic inspiration.

“This improper prorogation should hence not proceed. MPs may seek to block it, and so may the courts. The preferable route would be for the government to recognise its mistake and reverse it.”