Tony Blair is odds-on favourite to be next to join the new Independent Group.

The former Prime Minister joins Alistair Campbell, Heidi Allen and Nicky Morgan on a list of the potential next big names to join the group.

It follows news that three Tory MPs have quit their party to join the centrist faction.

Sarah Wollaston, Heidi Allen and Anna Soubry joined eight Labour MPs, with rumours circulating that more politicians are likely to jump ship.

The Independent Group have been priced at 5/2 to form part of a coalition government after the next General Election.

According to the latest Westminster intention it would garner 14 per cent of the vote if a vote was held tomorrow.

Betway’s Alan Alger, said: “This week has been one of the most dramatic in party politics since the formation of the SDP in the early 80s, and we think the defections to The Independent Group are only just starting.

“With three former Conservatives joining, The Independent Group is positioning themselves as a centrist having been between the two traditional major parties. We make them 20/1 to win the most seats at the next General Election.

“With British politics becoming increasingly fractured, The Independent Group could have a major say in the future of the UK. At 5/2 to be part of a coalition government after the next General Election, their influence and numbers may be key in the kingmaking in parliament.

“Like all things Westminster, the rumour mill is flying as to who the next big name to join the group will be,and we make Tony Blair the 5/2 favourite to be the next public figure to join Labour’s new breakaway group.”

Tony Blair hinted at a creation of a new UK centrist party last year, announcing that he had urged “serious figures” in both Labour and the Conservatives to demand change of their leadership.