Every Labour MP has been asked whether they intend to stand at the next general election as the first re-selection process under the party's new rules begins.

In an email to the Parliamentary Labour Party (PLP) this afternoon, general secretary Jennie Formby told MPs they had a fortnight to confirm whether they wished to remain a candidate. The move, which comes as speculation of an early election grows, is the first stage of the formal selection process that could see sitting MPs replaced as Labour candidates, Formby confirmed.

"Today, the NEC Officers met and agreed the procedural guidelines for re-selection of sitting Members of Parliament. The first stage is to collate the intentions of sitting MPs," she wrote.

"I am therefore writing to ask you to inform the Labour Party if you wish to remain a candidate at the next General Election?"

MPs have until 8 July to notify the party of their intentions and news that the formal selection process has begun is likely to stoke anxieties among some Corbynsceptics in the PLP. This round of selections will be the first conducted under new rules agreed by Labour's ruling National Executive Commitee at last year's party conference, which make it significantly easier for constituency parties to deselect sitting MPs.

A full selection was previously only permitted if more than half of a Constituency Labour Party's branches and of its affiliated trade unions and socialist societies demanded one. As of last September, however, an open selection can be triggered with the support of only a third of either local party or union branches.

Though the so-called 33 per cent model falls short of the mandatory reselection process favoured by some on the Labour left, it is likely to see far more incumbent MPs subjected to contested selections than on previous occasions. In this respect, Corbyn's supporters and his critics are in rare agreement: both believe Formby has kick-started a process that could drastically change the appearance of the PLP.