Jeremy Corbyn is facing calls to consider his position after Labour crashed to a humiliating defeat defeat in the Copeland by-election.

MPs warned the party was on course for a "catastrophic" general election defeat after the Conservatives snatched the Cumbrian seat which had been held by Labour since 1935.

The Labour leader admitted the result had been "very disappointing" but made clear that he was determined to carry on.

"I was elected to lead this party. I am proud to lead this party," he told reporters.

"We will continue our campaigning work on the NHS, on social care, on housing."

Critics on the backbenches warned however that he had become an "obstacle" to victory and urged him to step down in the interests of the party.

The victory for Tory candidate Trudy Harrison was the first time a governing party had gained a seat in a parliamentary by-election since 1982 and represented a historic achievement for the party after seven years in office.

There was some consolation for Labour in Stoke-on-Trent Central, where it saw off a concerted challenge from Ukip leader Paul Nuttall - albeit with a reduced majority.

But there was despair among Labour MPs at the defeat in Copeland in an area which has long been regarded as safe Labour territory.

John Woodcock, the MP for neighbouring Barrow-in-Furness, said the party was not an effective opposition and had to do better.

"There are always excuses you can make. But we are in trouble as a party," he told the BBC Radio 4 Today programme.

"We are on course to a historic and catastrophic defeat and that will have very serious consequences for all of the communities that we represent."

Senior Labour backbencher David Winnick said it had been a "disastrous" result for the party and urged Mr Corbyn to consider his position.

"The party is faced with the problem of a leader who is simply not acceptable to a large number of people who would normally vote Labour. That it is an obstacle and it would be wrong not to recognise that," he told the Press Association.

"It is now entirely up to Jeremy and those close to him to decide what is best in the interests not simply of the party but the people we are in politics to represent."

Despite the despair among Labour backbenchers there appeared to be little appetite for a fresh leadership challenge after Mr Corbyn's crushing victory in last year's contest.

"That would be quite useless. It would end in the same result as previously," Mr Winnick said.

On a tumultuous night, Ms Harrison polled 13,748 votes to 11,601 for Labour's Gillian Troughton, increasing the Conservative vote share by more than 8% as Labour's dropped by nearly 5%.

Shadow chancellor John McDonnell, one of Mr Corbyn's closest allies, said there had been "unique" factors in Copeland which is heavily dependent on the Sellafield nuclear facility.

He said the party had had enough of "macho leaders" and that voters would respond to Mr Corbyn's consensual approach .

"Jeremy has a sense of duty. He will lead this party. He will rebuild it as a social movement, as we are doing now, and on that basis we will win the next election and he will be the prime minister," he told the Press Association.

He also hit out at Tony Blair and Lord Mandelson for high-profile interventions in the days before the by-elections.

"We can't have a circumstance again where a week before the by-election a former leader of our party attacks the party itself," he told the Today programme.

In a speech in London, Mr Corbyn said: "Labour's victory in Stoke-on-Trent Central was a decisive rejection of Ukip's politics of division and dishonesty, and I congratulate Gareth Snell on his election.

"But our message was not enough to win through in Copeland, and I congratulate Gillian Troughton on the campaign that she fought.

"In both campaigns, Labour listened to thousands of voters on the doorstep. Both constituencies - like so many in Britain - have been let down by the political establishment. To win power to rebuild and transform Britain, Labour will go further to reconnect with our supporters and voters in general."

Ukip was also forced on to the defensive after Mr Nuttall's gamble of standing in Stoke Central failed to pay off, despite overwhelming support for Brexit in the city in last year's EU referendum.

After Gareth Snell held the seat for Labour with 7,853 votes to Mr Nuttall's 5,233, Ukip chairman Paul Oakden acknowledged it could take years before they manage to win a seat in Westminster.

"Politics is a long game. It took us 23-odd years to win a referendum to get Britain out of the European Union," he told the BBC Radio 4 Today programme.

"It may take that long for us to get a seat in Westminster via a by-election. But if that's how long it takes then that's what we will keep doing, because that's what we are here for."

Fielding questions following his speech, Mr Corbyn was asked whether he had this morning "looked in the mirror and asked yourself the question: 'Could the problem actually be me?'"

The Labour leader replied simply: "No."

Asked why not, he said only: "Thank you for your question."

Downing Street dismissed suggestions that Theresa May could call a snap general election in the wake of the Copeland result.

"The PM has set out the position very clearly on a general election. There are no plans for one," a No 10 spokesman said.