Trudy Harrison has won a historic victory in the Copeland by-election for the Conservatives winning by a majority of 2,147 votes over Labour.
The Conservative Trudy Harrison beat her main challenger Labour's Gillian Troughton with a majority of 2,147.
He said Mr Corbyn needed to show that he understood how to "turn things around and deliver" - because ordinary people needed a Labour government now.
"What we've seen from this victory is this truly is a government that's working for everyone and every part of the country - and that's the message that we bring here to Copeland and we'll take across the country."
The Tories won with a 6.7% swing away from Labour, a catastrophic result for the party's far-left leader Jeremy Corbyn.
"This is a quite exceptional result and while there are particular factors (Copeland is home to the Sellafield nuclear plant) we simply should not be losing seats like this".
The victory is made even sweeter by the fact that Ukip's candidate was none other than party leader Paul Nuttall; his failure to gain a seat is a severe setback for the anti-immigrant movement which, despite gaining 12.6 per cent of the vote at the last general election in 2015, has only one parliamentary seat. Indeed, it would be better to have the Conservatives in power lest anyone thought that a Labour Party which is betraying the interests of the working class actually meant something.
S&D sources told EURACTIV.com that for the next two years, "We will provide them with information regarding the negotiations as they can not rely on the government".
Theresa May's Conservatives are on the verge of destroying UKIP, and Jeremy Corbyn is doing what he can to ruin Labour.
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Stoke and Copeland share a sense of being neglected, perhaps why both constituencies voted Leave in the European Union referendum.
Baroness Smith also ridiculed claims by some Labour frontbenchers who tried to play down the significance of the Copeland result, and rejected suggestions that Tony Blair had undermined the party's performance with critical remarks about Corbyn. The constituency of Copeland in north- west England has been solidly Labour for nearly a century, while the other parliamentary seat, Stoke-on-Trent Central nestled in one of the most attractive mountainous areas in the heart of England, has voted Labour since 1950.
"Let us not be in any doubt about what these results represent", she said.
That prompted Shadow Chancellor John McDonnell to boast: "We've turned back the tide, and I think we've defeated quite a unsafe form of politics".
"In both campaigns, Labour listened to thousands of voters on the doorstep".
He said: "The Copeland meltdown is at Len McCluskey's door".
Appearing on Channel 4 News, Baroness Chakrabarti was asked if she would like the Labour leader to face a general election "sooner rather than later".
Voters deserted the party in droves as it lost a seat to the Tories which it had held since 1935.
He said: "I was elected to lead this party, I was elected to oppose austerity and to oppose the redistribution of wealth in the wrong direction, which is what this Government is doing".