THE SNP, Plaid Cymru and more have signed a pact to change the UK voting system.

The LibDems, Brexit Party and Alliance Party of Northern Ireland have also backed a push by the Make Votes Matter campaign to enact a new system to improve democracy.

The UK is the only state in Europe, and one of only three major democratic developed states, to use first-past-the-post for general elections. Campaigners claim that means the Westminster parliament does not reflect the votes cast, encourages tactical voting and ends up "shutting millions out of politics".

The Good Systems Agreement, which calls for a proportional system to replace first-past-the-post, has also won the support of individual Tory and Labour MPs.

Tommy Sheppard, SNP MP for Edinburgh East, said: “I want Scotland to become an independent country so that we work together with other countries in Britain and Europe on our own terms. But for as long as we are part of the United Kingdom, we will defend the democratic principle of a parliament that reflects the people.

"I believe both Scotland’s and the UK’s interests will be better served by a House of Commons that is representative of the voters and capable of compromise – perhaps occasionally even of consensus.”

According to Makes Votes Matter, a citizens' assembly should be set up to decide the exact form a new system would take. However, it should be proportional and allow all votes to count equally "wherever in the UK they are cast".

The agreement says any new system should maintain the geographical link between MPs and constituencies and also allow the public to vote for "people rather than just parties".

The parties backing the call, including the SNP, secured more than two thirds of all votes cast in the recent European elections.

Derek Thomas, Tory MP for St Ives, commented: “The first-past-the-post voting system we use for general elections means that many voters do not feel they have a stake in our democracy. Electoral reform alone will not return trust to politics, but I believe we have little chance of truly rebuilding trust without it. This is why I have joined a new cross-party agreement.”

Klina Jordan, co-founder of Make Votes Matter, said: “The current system is failing on its own terms so badly that the next general election will likely produce another government without a clear majority. When that election comes around, this agreement will be at the forefront of any negotiations that follow.”