A fresh push for a proportional representation voting system has been launched by a group of MPs from almost every party in Parliament.

They are proposing a motion to the House of Commons which declares the current voting system not "fit for purpose" and calls for the Government to implement a switch to PR.

It follows petitions calling for the change that have received the backing of some 500,000 people.

Senior Labour figure Chuka Umunna, who proposed the motion, said: “Since the general election last year, the pressure is building and a consensus is coming together behind the need to change the system.

"The Brexit vote has added to that, underlining people’s discontent with the voting system."

The motion laid today has also been signed by representatives from the Liberal Democrats, Greens, Ukip, the SNP and Plaid Cymru.

It states, "the current system of electing Members of Parliament is no longer fit for purpose” and adds “that the share of seats a party gets should closely reflect the share of votes that people give them".

It then demands the Government, "bring forward legislation to introduce a system of proportional representation for elections to the House of Commons."

Currently, the Chamber is elected using "first past the post", giving each party a share of seats that is out of line with the share of the votes cast.

Supporters of the current system say this is acceptable because it usually delivers a strong single-party government.

But smaller parties claim they are penalised by FPTP. At the 2015 election a combined vote of almost 5 million secured just one seat each for the Greens and Ukip.

A previous Bill proposed by the Greens to bring in a PR system received cross-party support but was ultimately voted down in the Commons.