- Analysis by ITV News Deputy Political Editor Chris Ship
Another by-election is probably the last thing Jeremy Corbyn wanted for his troubled Labour Party.
It's been brought about by the resignation of the MP for Stoke Central, Tristram Hunt, who's to become director of the Victoria and Albert museum in London.
Mr Corbyn says he's not lost control of the party.
The question being asked tonight is, will more Labour MPs quit?
- Video report by Deputy Political Editor Chris Ship
Tristram Hunt quit as MP for Stoke-on-Trent today, triggering what could be a disastrous by-election for his Party - and leader Jeremy Corbyn.
He's been an outspoken critic of Mr Corbyn in the past, but in his resignation letter he insisted he didn't want to "rock the boat".
Labour will face a tough battle to retain his seat.
Jeremy Corbyn has thanked Tristram Hunt for his services to the Labour Party following the latter's resignation.
Hunt is set to stand down from his role as MP for Stoke-on-Trent to take up a new job as director of the Victoria and Albert Museum.
His departure has already been described by UKIP as a sign of MPs' disillusionment with Corbyn's leadership of the party.
Hunt stepped down from his role as shadow education secretary shortly after Corbyn's election as party leader in September 2015, citing their political differences.
In a short statement, Corbyn said: "I would like to thank Tristram Hunt for his service to the people of Stoke-on-Trent Central and to the Labour Party.
"I wish him well in his future role at the V&A."
Outgoing MP Tristram Hunt's resignation from Parliament is a sign of the times under Labour leader Jeremy Corbyn, according to UKIP.
Hunt's decision to ditch politics for a new role as director of the Victoria and Albert Museum shows how many Labour MPs see a "brighter future" away from the party.
UKIP chairman Paul Oakden said he expected many voters to desert Labour in Stoke-on-Trent's upcoming by-election - triggered by the former shadow education secretary's departure.
"The resignation of Tristram Hunt MP highlights the brighter future that many in the Labour Party feel they have away from Jeremy Corbyn and his brand of politics," Oakden said.
"We have no doubt that the example set by Mr Hunt will be one that many voters in Stoke-on-Trent will consider following in the upcoming by-election, where UKIP will be fighting hard to offer local people the committed representation they both need and deserve."
Tristram Hunt has called for the Labour party to "unite" with the public following Jeremy Corbyn's re-election as leader after a bitter contest with Owen Smith.
The former shadow education secretary has previously spoken out against Mr Corbyn's leadership of the party, saying the "experiment with Corbynism has to end".
Mr Hunt told Peston on Sunday: "All these calls for unity at the moment are absolutely right but the unity I want to see is between the Labour party and the British public, so we are now going to talk to the country rather than just the party."
Mr Hunt also said he was still not prepared to serve in Mr Corbyn's shadow cabinet because he had "deep political and philosophical differences" with the leader.
He called delays on the decision over shadow cabinet elections a "missed opportunity" and said he hoped de-selection of critical MPs would not happen.
Former Labour shadow education secretary Tristram Hunt has reportedly told students at Cambridge University the party is "in the s***".Read the full story ›
Chuka Umunna is among the big name Labour MPs who have left Brighton before Jeremy Corbyn makes his first conference speech as party leader.
ITV News' Chris Ship said Tristram Hunt and Mary Creagh were also among the prominent backbenchers who departed early.
A non-Corbyn supporting Labour MP (of which there r many) tells me Chuka's already gone. Out of town before the Leader even hits the stage
Most Labour MPs already know who they want as leader, according to Tristram Hunt, who has just announced he would not be standing.
In a speech setting out his vision for the party, he admitted he hadn't been able to drum up enough support for his own bid
"Like other potential candidates in recent days I have made a lot of calls to potential supporters among my parliamentary colleagues. I found that the bulk of MPs are already committed to just a couple of candidates," he said.
"It is surprising that the nomination process to select a leader for at least the next five years appears to have been largely decided within at most five days of a devastating general election defeat."
The MPs currently still in the race to become leader are Liz Kendall, Yvette Cooper, Andy Burnham, and Mary Creagh.
Tristram Hunt has announced that he will not stand in the forthcoming Labour leadership election.
In a speech, the MP for Stoke said he would be backing Liz Kendall for the leader's role instead.
He also strongly criticised the party's strategy at the general election, claiming Labour's welfare policies "offended the British people's sense of fairness".