The Conservative victory in the Cumbrian constituency marked the first time a United Kingdom governing party has seized a seat at a by-election since 1982. Harrison won the election with 13,748 votes (44.25%), more than 2,000 votes ahead of Labour's Troughton.
While the number of Labour Party members has increased since the election of Jeremy Corbyn as leader in September 2015, the number of votes and the support it is showing in opinion polls has fallen. "As John McDonnell said this morning, Labour lost Copeland because of Jeremy Corbyn's ambiguous attitude to nuclear power".
But ironically, on the same night he suffered the personal blow of losing Copeland, one of the defining decisions of his leadership - not to oppose Theresa May on Article 50 - was vindicated, at least to a degree, in Stoke-on-Trent Central, where the party ran a campaign demonstrating new-found enthusiasm for Brexit, a stance that probably helped their candidate Gareth Snell over the line in a constituency where almost 70 percent backed Brexit. However the campaign was dealt a blow when Nuttall, UKIP's candidate in Stoke and the party's leader, became embroiled in a controversy over a false statement about being on a charity board.
The European Parliament grand coalition between the right-wing European People's Party (EPP) and the Socialist and Democrats (S&D group) is over and can not be re-established, said its chief, Gianni Pittella, today (13 December) during a news conference in Strasbourg.
"We are on course for a historic and catastrophic defeat and that will have very serious consequences for all of the communities that we represent", he added. Had those who voted Lib Dem and Green in Copeland voted Labour, the Tories would have been defeated.
Mr Nuttall said Ukip was "not going anywhere" and insisted the party's "time would come".
Neither of the two resigning MPs directly attacked Jeremy Corbyn's leadership in their resignation letters, but both have been outspoken critics of the direction he was taking.
"Labour's local branches are changing", the PM said.
"So we're saying to those people... unite because people will then see the real Labour party campaigning and we'll win back places like Copeland", he said. May's Conservatives won the district for the first time since its creation in 1983 - an achievement all the more remarkable because it's exceptionally rare for British governing parties to gain seats in such special elections.
Former chancellor of the exchequer George Osborne commented on social media "How much longer is the Labour movement going to put up with its utterly useless, shambolic and frankly embarrassing leadership?"
"We did not get the message across that the Labour party was pro-civil nuclear", he said afterwards.
Andrew Gwynne MP, Labour's campaign manager, was visibly upset after the result was announced. "Copeland shows that", he said.
That prompted Shadow Chancellor John McDonnell to boast: "We've turned back the tide, and I think we've defeated quite a risky form of politics".