A dramatic swing of almost 30% from the Tories to the Liberal Democrats saw Richard Foord secure a majority of 6,144.
In Wakefield, Simon Lightwood was elected with a majority of 4,925 on a swing of 12.7% from the Tories to Labour.
The contests, which were triggered by the resignation of disgraced Tory members, offered voters the chance to give their verdict on the Prime Minister just weeks after 41% of his own MPs cast their ballots against him in a confidence vote.
Follow the latest updates from the by-election below.
Live: Tory party suffers double defeat in crunch by-elections
Last updated: Friday, 24 June, 2022, 14:15
Nadine Dorries compares Boris Johnson’s by-election defeats to Margaret Thatcher
Culture Secretary Nadine Dorries has compared Boris Johnson’s by-election defeats to that of former Prime Minister Margaret Thatcher.
Ms Dorries said that the government remains “relentlessly focused” in the face of the results, before rubbishing claims that the Tory defeats were the start of the downfall for the party, saying that they did not have a “shred of substance”.
She said: “Last night was a reminder that we must be relentless in cracking on with the job of delivering. Under Boris Johnson we are massively investing in digital infrastructure which is accelerating growth and employment in our rapidly expanding tech sectors.
“However, history tells us how useless by election results are as an indication of absolutely anything at all. Margaret Thatcher would not have won 3 GEs (general elections) and would have served for a very short time as PM if some of the claims I’ve heard today were based on a shred of substance.
“This gov will remain relentlessly focused and continue to deliver for people during a post pandemic, mid-war, global cost of living challenge which no Prime Minister or gov has faced the likes of since WW11 (sic).”
Lib Dems: ‘no pact with Labour to beat Tories'
Sir Ed Davey has said the Liberal Democrats have no pact with the Labour Party to beat the Conservatives, after the Tories suffered a double loss in two by-elections.
Speaking to reporters at a post-election rally in Tiverton, Sir Ed said: “I am being honest with people there is no pact, there is no deal, but the Liberal Democrats are fighting in areas we believe we can win.
“Here in Devon and the West Country we have had a legacy of lots of MPs and councillors over decades.
“It was very clear Tiverton & Honiton was a seat we could win if we campaigned hard.”
Ex-Tory leader Michael Howard calls for Boris Johnson to resign
Former leader of the Conservative Party Michael Howard has called for Boris Johnson to resign, the BBC has said.
The corporation quoted the Tory peer as telling its World at One programme: “The party and more importantly the country would be better off under new leadership.”
In a post on the World at One’s Twitter account, the BBC says he added: “Members of the Cabinet should very carefully consider their positions.”
Video: Keir Starmer hails ‘great result for Labour’ after Wakefield by-election win
Nicola Sturgeon: by-election losses ‘monumental and humiliating’ for PM
Scotland’s First Minister has branded the Conservative Party by-election losses as “monumental” and “humiliating” for the Prime Minister.
Speaking from the Royal Highland Show on Friday, Nicola Sturgeon urged Tory MPs to remove Boris Johnson.
She said: “It’s a monumental, massive, humiliating vote of no confidence in Boris Johnson.
“People could see it coming 100 miles off and it should send a very strong message – if not to Boris Johnson, who is impervious to all of these things given his arrogance, it should send a very strong message to the Conservatives.
“If they keep Boris Johnson, a law breaking Prime Minister who has been seen to not tell the truth, if they keep him in office, then effectively they are all becoming complicit in this.
“If this is not a wake-up call to the Conservative Party, then it will just prove beyond doubt that they don’t have the interests of any part of the UK in mind or at heart.”
Oliver Dowden’s resignation a ‘loss’ to the government
Priti Patel has said Oliver Dowden’s resignation as chairman of the Conservative Party was a “loss” to the government.
The Home Secretary said it is “important that we really reflect” on the by-election results, while also recognising the contests were fought against a “difficult and challenging backdrop”.
When it was put to her that recent results show Conservative voters are switching to the Liberal Democrats, she told Times Radio: “Well actually I wouldn’t say that at all, I really wouldn’t. I think that is quite a wide assumption.”
Sir Keir: ‘huge result for Labour’
Sir Keir Starmer said the win in Wakefield was a “huge result for the Labour Party”.
Simon Lightwood was elected with a majority of 4,925 on a swing of 12.7% from the Tories to Labour.
The Labour leader told reporters in Ossett: “This puts us now absolutely on track for a Labour government, which is absolutely coming.”
Saying that 12.69% was a “significant” swing towards Labour, he added: “That tells you that the next government is going to be a Labour government, and the sooner the better – because the country voted yesterday in both by-elections, no confidence in this out-of-touch, out-of-ideas government.
“This is a historic by-election as far as we’re concerned.”
Senior Tory MP says Oliver Dowden’s resignation was ‘honourable'
Senior Tory MP Tobias Ellwood said Oliver Dowden’s resignation was “honourable”.
‘Beginning of the end’ for PM
Former Conservative MP and minister Rory Stewart said the resignation of Tory party chairman Oliver Dowden “feels like the beginning of the end” for Boris Johnson.
Sharing a copy of Mr Dowden’s resignation letter, he tweeted: “A devastating resignation for Boris Johnson because it comes from one of his earliest and most passionate supporters, who backed many of his cultural fights, and risked his reputation defending him for years.
“This feels like the beginning of the end.”
Veteran Tory says PM has ‘trashed’ party reputation
Veteran Tory MP Sir Roger Gale said Boris Johnson had “trashed” the reputation of the Conservative Party.
Sir Roger said Mr Johnson was choosing to “hang onto the door handle at No 10” but “it can’t go on forever and it certainly won’t go on until the next general election”.
He said the Tories were “spoilt for choice” for new leaders and there are “several people” who he believes would make a good Prime Minister
Asked if he saw Oliver Dowden’s resignation as a trigger for more expressions of discontent from the Cabinet, he told BBC Breakfast: “It is possible that that may happen but it is up to my colleagues in the Cabinet to decide whether they can go on supporting a Prime Minister who, frankly, has trashed the reputation of the Conservative Party, my party, for honesty, for decency, for integrity and for compassion.”
He added: “There are several people who would make very good prime ministers within the party and one of those will emerge between now and the next general election and lead us into the next general election, which I trust we shall win.”