Labour MP says the party shouldn't rule out a 'grand coalition' with the Tories

The Labour MP of Birmingham Edgbaston, Gisela Stuart, has suggested that the party should not rule out the possibility of forming a coalition government with the Conservatives after the General Election.

Stuart told the Financial Times: "If on May 8 you had a position where Labour had more seats than the Tories but not enough to form a government - but the Tories had more votes than Labour - I think you should not dismiss the possibility of a grand coalition in terms of regrouping of the main."

The suggestion is a radical one. There is no precedent for such a "grand coalition" in Britain outside of the all-party National Government coalitions in the First and Second World War.

To give you an idea of just how extraordinary such a deal would be, on current projections by Election Forecast UK a coalition between Labour and the Conservatives would mean a government with 563 seats of a possible 650 MPs in the House of Commons (with 326 seats needed for a majority).

But there's a reason why these grand coalitions are traditionally strongly resisted by party members - the UK's two largest parties are defined (and, more importantly, their supporters define themselves) by their opposition to one another. Coming together to form a government in peacetime would effectively tell the electorate that the differences between the two are (largely) cosmetic and there are more similarities imn their policies than fundamental points of difference.

That's a big problem. Just look at what has happened to the poll numbers of the Liberal Democrats, Britain's erstwhile third party, since it elected to join a coalition with the Conservatives in 2010 - they've collapsed.

In other words, a "grand coalition" isn't going to happen unless David Cameron and Ed Miliband decide to commit political harakiri or the UK goes to war in the next four months.