- Mordaunt becomes first to declare intention to run
- Candidates need to reach target of 100 nominations
- Sunak is the bookmakers' favourite
- Winner would be fifth British PM in six years
LONDON, Oct 21 (Reuters) - Boris Johnson has been gaining momentum in his audacious bid to return as British prime minister, with his colleagues deeply divided over the potential comeback and some warning he would plunge the country into fresh chaos.
Former defence minister Penny Mordaunt became the first candidate to officially declare an intention to run to be the next leader of the Conservative party, but Johnson and Rishi Sunak, once his finance minister, led potential contenders as candidates canvassed support ahead of voting next week.
With the Conservatives holding a large majority in parliament and able to ignore calls for a general election for another two years, the new party leader will become prime minister - Britain's fifth in six years.
Those seeking to replace Liz Truss, who quit on Thursday after six chaotic weeks, must secure 100 nominations from Conservative lawmakers by Monday. Truss herself succeeded Johnson after he was ousted by his colleagues in July.
The party hopes the contest will revive its ailing fortunes. Opinion polls suggest the Conservatives would be all but wiped out if a national election were held now.
Johnson has not formally announced he will run but five cabinet ministers threw their weight behind him, while media reports suggested Sunak became the first leadership candidate to hit the threshold to enter the contest before Monday's deadline.
A Reuters tally of Conservative lawmakers who have made public declarations of support put Sunak on 70 backers, Johnson on 37 and Mordaunt on 20.
A return to the top would be an extraordinary comeback for Johnson, who remains popular with party members - although a YouGov poll of 3,429 adults conducted on Friday found 52% of Britons would be unhappy to see him return as prime minister.
Conservative lawmaker James Duddridge said Johnson told him he is "up for it" and the former leader will fly back to Britain on Saturday from a holiday in the Caribbean.
But some queried whether Johnson, who left office comparing himself to a Roman dictator twice brought into power to fight crises, could clinch 100 nominations. His three-year premiership was blighted by scandals and allegations of misconduct.
The former Conservative leader William Hague said Johnson's return was possibly the worst idea he had heard in almost half a century as a party member. He said it would lead to a "death spiral" for the Conservatives.
Sunak, a former Goldman Sachs analyst who became finance minister just as the COVID-19 pandemic hit and was runner-up to Truss in the last leadership contest, is the bookmakers' favourite, followed by Johnson. Mordaunt is again placed third.
The winner will be announced next week. If there is only one candidate with over 100 nominations from lawmakers by Monday that person will be announced as the winner; if three candidates reach the threshold, a vote by lawmakers on Monday will eliminate one candidate, with party members then choosing between the remaining two and the winner announced on Friday.
Truss, whose economic plans proved disastrous, will be Britain's shortest-serving prime minister.
The sight on Thursday of yet another unpopular premier making a resignation speech in Downing Street underscored how volatile British politics has become since the 2016 Brexit vote.
Luxembourg's Prime Minister Xavier Bettel said leaving the European Union had brought instability to Britain.
"I hope that they will soon be stable because even if they are not a family member any more they are a friend and a neighbour," he told reporters in Brussels.
Johnson, the face of the Brexit campaign, led his party to victory at the last general election in 2019, prompting many Conservatives to argue that he alone has a mandate as leader. But members of the public were not all convinced.
"I think they're assuming that he will win the next election because he did so well in the last election. But a lot has changed since then. And I think he's shown to completely lack integrity," said former accountant Fiona Waldron, 60.
Opposition parties, some newspapers and even a few Conservative lawmakers have called for a general election to be held.
The Conservatives "cannot respond to their latest shambles by yet again simply clicking their fingers and shuffling the people at the top without the consent of the British people," Labour Party leader Keir Starmer said.
"They do not have a mandate to put the country through yet another experiment."
Some Conservative lawmakers have urged colleagues to coalesce around one candidate to avoid a bruising battle.
Sunak, who warned that Truss's fiscal plans risked economic instability, is unpopular with some party members after he helped trigger the rebellion against Johnson.
Mordaunt is seen as a fresh face, but is also untested.
The next leader will inherit an economy bound for recession, with rising interest rates and inflation over 10% leaving millions facing a cost-of-living squeeze.
Surveys on Friday showed gloomy British shoppers reining in spending, while worse-than-expected public borrowing figures underscored the economic challenges ahead. Truss's spokeswoman said her successor would decide whether to proceed with a fiscal plan scheduled for Oct. 31.
Whoever takes over will have a mountain to climb to restore the party's reputation.
"Whether or not a change of leader is going to be sufficient to make the Conservatives actually electorally credible is certainly highly debatable," political scientist John Curtice told LBC.
Our Standards: The Thomson Reuters Trust Principles.