The Liberal Democrats bore the brunt of anti-coalition sentiment in 2015 when their 57 MPs were reduced to just eight.
The party did not fare much better in the 2017 Election, winning 12 seats.
But defections from Labour, the Conservatives and Change UK in the past few months, along with Jane Dodds winning the Brecon and Radnorshire byelection in August, have swelled the Lib Dem ranks to 21.
The latest is Antoinette Sandbach, who joins a gang of eight rebels.
So who are they?
On February 18, Mr Umunna and six other Labour MPs resigned from the Labour Party in protest at Jeremy Corbyn’s leadership.
They formed The Independent Group, which later changed its name to Change UK .
But on June 13, Mr Umunna was on the move again, joining the Lib Dems and saying he had “massively underestimated just how difficult it is to set up a fully fledged new party without an existing infrastructure”.
The former Conservative and Change UK MP became a Lib Dem on August 14.
In 2011 Dr Wollaston supported a bill that required MPs who switch parties to face an automatic by-election, but she did not resign after either of her party changes this year.
She initially supported leaving the EU in the 2016 referendum, but changed sides shortly before the poll, saying Vote Leave’s assertion that leaving the bloc would make available £350m a week for health spending “simply isn’t true” and represented “post-truth politics”.
On September 3, Dr Lee crossed the floor to join the Lib Dems during a speech by Boris Johnson on Brexit.
His resignation left the Government without a working majority in the House of Commons.
Dr Lee’s resignation letter to the Prime Minister said he had “reached the conclusion that it [was] no longer possible to serve [his] constituents’ and country’s best interests as a Conservative Member of Parliament”.
Ms Berger left the Labour Party in February to become a founder member of The Independent Group.
In June, she left what was now called Change UK to sit as an independent MP, then, on September 5, Ms Berger joined the Lib Dems saying its anti-Brexit stance was the main reason behind her move.
Her current seat is Liverpool Wavertree, but she has been selected as her party’s candidate for Finchley and Golders Green in London for the General Election.
Ms Smith left Labour in February for The Independent Group and, subsequently, Change UK.
On September 8 she defected to the Liberal Democrats.
She is currently the MP for Penistone and Stocksbridge, but will stand in Altrincham and Sale West in the General Election.
Mr Gyimah defected from the Conservatives on September 14, during the Liberal Democrat’s party conference.
He was one of a group of 21 Tory MPs who lost the party whip on September 3 for voting to block a no-deal Brexit.
In June he announced that he would stand as a candidate in the Conservative Party leadership election on a platform of holding a second Brexit referendum, but later withdrew.
Ms Allen resigned from the Tories in February to join The Independent Group and became interim leader of Change UK in March.
In July she founded a group of MPs called The Independents, but on October 7 it was announced that she had joined the Lib Dems and would stand for the party in her South Cambridgeshire constituency at the next election.
However, on October 29 Ms Allen announced she would not stand in the upcoming General Election, saying she was “exhausted by the invasion into my privacy and the nastiness and intimidation that has become commonplace”.
On October 31 Antoinette Sandbach joined the Lib Dems and will contest her Cheshire seat of Eddisbury as its candidate.
She was one of 21 Tories who had the party whip removed after rebelling against the Government in a September Commons vote.
She said the upcoming General Election will be “the most important in my lifetime”.