British Prime Minister Boris Johnson has been dealt a significant blow after the Conservatives lost the Brecon and Radnorshire by-election to leave him with a working majority of just one.

Mr Johnson's first major challenge as Tory leader became his first major defeat with the announcement of Jane Dodds' victory for the Liberal Democrats in the early hours of this morning.

The Tory loss in Wales will add to the PM's challenges to steer Brexit through parliament and may increase the chances of a snap general election.

Conservative candidate Chris Davies was the constituency's MP until he was ousted in a recall petition after he admitted submitting false invoices for expenses.

Despite 19% of the electorate petitioning for his recall, the Tories selected Mr Davies to fight to reclaim the seat.

The vote may also be seen as an early victory for the "Remain alliance" of anti-Brexit parties, with Plaid Cymru and the Greens agreeing not to field candidates in order not to split the pro-EU vote.

Mr Davies won the seat from the Lib Dems in 2015 and secured a majority of 8,038 in the 2017 general election.

The loss leaves Mr Johnson with the support of 319 MPs, including the DUP which props up his majority, while opposition parties now have 318.

Mr Davies' recall came after he pleaded guilty in March to submitting two false expenses invoices for nine photographs costing £700 to decorate his new office.

He was fined £1,500, ordered to pay £2,500 towards legal costs and told to carry out 50 hours of community service. 

Welsh Lib Dem leader Ms Dodds said: "My very first act as your MP when I arrive in Westminster will be to find Mr Boris Johnson wherever he is hiding and tell him loud and clear, 'Stop playing with the future of our communities and rule out a no-deal Brexit now'."

Tory chairman James Cleverly said it was "disappointing to lose a parliamentary colleague" but, attempting to put a brave face on the defeat, he told BBC Radio 4's Today: "What we saw was a very close result in a by-election in which the Lib Dems were expected to romp home comfortably."