Finishing her speech with a direct challenge to Mr Sunak, she said: “My message to the Prime Minister is get in your government car, drive to Buckingham Palace, do the decent thing and call a general election.”
According to Electoral Calculus founder Martin Baxter, Labour could expect a majority of roughly 200 seats if it repeats its performance in Tamworth in the next general election.
Mr Cooper, a Tamworth councillor, attempted to fight the by-election campaign on his local credentials.
However, he attracted controversy when a social media post from 2020 was unearthed, where he suggested out-of-work parents who struggled to feed their children but paid for phone contracts should “f— off”.
Mr Cooper, who earned 10,403 votes to Ms Edwards’ 11,719, just spent minutes on stage at the final count, arriving late as the declaring officer apologised for the “brief intermission”.
He exchanged a terse handshake with the Labour candidate before rushing through a back door as the results were read out, pursued by a press pack. Ms Edwards later said his early exit was “disappointing”.
Lord Hayward, the Tory pollster, suggested Tamworth had a pool of Labour supporters whose support had been underestimated because they had not turned out in recent elections as they would for Sir Keir Starmer.
He said the Conservatives had benefitted in 2017 and 2019 from a dip in the Labour vote, dragged down by the unpopularity of former leader Jeremy Corbyn.
“There is a very substantial pool of Labour voters, more there than the actual majority implied,” he told The Telegraph.
The anti-Labour vote appeared to have been split with Reform, the successor to Nigel Farage’s Brexit party. Taken together, the Conservative and Reform votes would have been enough to secure a narrow victory in the seat.
None of the other third parties – including the Liberal Democrats – managed to keep their deposit as their share of the vote was squeezed out by the Tories and Labour.
Turnout was lower than in recent by-elections, although Ms Edwards denied that her victory owed more to Tory indifference than a wave of support for Labour. Earlier in the night, the Conservative’s local campaign chief suggested this showed Sir Keir had failed to energise the electorate.
Pointing to the party’s 23.9 per cent swing, Ms Edwards told The Telegraph: “Conservatives voted for Labour because they could no longer tolerate the awful situation they had been placed in both locally and nationally.”