BORIS Johnson has admitted the Chesham and Amersham by-election was a “disappointing result” after the Liberal Democrats inflicted a severe defeat on his Conservative Party.

Sarah Green is the country’s newest MP after winning the Buckinghamshire seat, which had been a Conservative stronghold since its creation in 1974.

LibDem leader Sir Ed Davey said his party’s victory would “send a shockwave through British politics” while claiming the result demonstrated that the “Blue Wall” of Tory southern seats could be vulnerable.

The Prime Minister thanked defeated Tory candidate Peter Fleet and said there were “particular circumstances” at play after his party lost one of its safest seats in England.

Asked if he was neglecting voters in the South in favour of those in the North, the Prime Minister told reporters: “It was certainly a disappointing result.

“There were particular circumstances there and we are getting on with delivering our agenda for the whole country, that’s what one-nation Conservatism is all about. We believe in uniting and levelling up within regions and across the country.”

The by-election was triggered by the death of former Cabinet minister Dame Cheryl Gillan, who took the seat with a majority of 16,233 in the 2019 General Election – some 55% of the vote.

In a stunning result, Green took 56.7% of the vote to secure a majority of 8028 over the second-placed Tories. Davey told BBC Breakfast: “I think this will send a shockwave through British politics. Liberal Democrats have had good wins in the past, but this is our best-ever by-election victory, and if it was repeated across the South, literally dozens of Conservative seats would fall to the Liberal Democrats.

“People talked about the Red Wall in the North, but forgotten about the Blue Wall in the South, and that’s going to come tumbling down if this result is mimicked across this country.”

The Green Party came third with 1480 votes, with Labour trailing in fourth with just 622 votes, losing the party’s deposit in the process.

Polling expert Sir John Curtice told BBC Radio 4’s Today programme that he made it the “worst Labour performance in any by-election” after the party took just 1.6% of the vote.

In her acceptance speech, Green said: “The voice of Chesham and Amersham is unmistakable. Together we have said: ‘Enough is enough, we will be heard, and this Government will listen’.

“This campaign has shown that no matter where you live, or how supposedly safe a constituency may appear to be, if you want a Liberal Democrat member of Parliament, you can have a Liberal Democrat Member of Parliament.”

Green and Davey celebrated the triumph at a victory rally in the constituency, where they stood in front of a blue wall made of plastic bricks which the LibDem leader then smashed with an orange hammer.

Major issues in the campaign included the HS2 rail line, which cuts through the constituency, and proposed planning reforms which have sparked fears about building in the countryside around the seat in the Chilterns.