The small rump of 121 Tory MPs who survived the party’s general election drubbing will return to Westminster on Monday with one item on their agenda – choosing the man or woman to take the fight to Keir Starmer for the next five years.

They will hardly have time to draw breath before the first ballot of the contest takes place 48 hours later, when one of the six candidates will be unceremoniously dumped by their colleagues.

Kemi Badenoch, Robert Jenrick, Mel Stride, Priti Patel, James Cleverly and Tom Tugendhat await their verdict, which will be delivered by Bob Blackman, chair of the 1922 Committee of Tory backbenchers, in committee room 14.

Stride, a close ally of outgoing leader Rishi Sunak and the man who was rarely off our TV screens during the general election campaign, is seen as the most likely to fall at the first hurdle.

But many Tory MPs have told HuffPost UK that the outcome of Wednesday’s ballot is too close to call, and that Stride could well survive at the expense of a more fancied rival.

One former cabinet minister said: “I wouldn’t bet on Mel going in the first round. He’s got a hardcore of support in the parliamentary party and 15 or 20 MPs might be enough to get him through the first round.”

A veteran MP added: “I think Rob and Kemi will come first and second, but any one of the other four could go on Wednesday. It will be very close and a few votes here and there could swing it.”

Although Badenoch remains the bookies’ favourite to emerge victorious in the end, many MPs have been surprised by her relative anonymity over the summer.

While her five rivals have been criss-crossing the country meeting party members and doing media interviews, the shadow communities secretary has made a virtue of taking two weeks off to recharge her batteries.

“Articles portraying politicians negatively for having a family life have done much to toxify the environment for MPs – we can do better than this,” Badenoch said earlier this month as she defended her decision to go on holiday with her family while parliament is in recess.

In a quote almost designed to annoy her rivals, a Badenoch ally told Guido Fawkes: “The general election campaign was long and hard and painful. I seriously doubt any Tory members, candidates or MPs will seriously begrudge the next leader of the Conservative Party having some time away with her family.”

But one currently undecided Tory MP told HuffPost UK: “I think Kemi has under-performed so far. It’s been a very casual campaign. I think the story after Wednesday will be that she has performed below expectations.”

A shadow cabinet member said: “A few colleagues have expressed surprise at Kemi’s decision to go on holiday. We’re all knackered after the election, but if you want to be turning round the fortunes of the party you have to show that hunger.

“Some people are wondering whether she lacks the necessary drive. There have been questions about her work ethic in the past.

“The initial view was that Kemi would come racing out the blocks with big name endorsements to build up a lot of momentum, and there’s a lot of surprise that that hasn’t happened.”

But a Badenoch aide hit back: “The MPs complaining to you are backing other candidates and trying to make this a thing, but it isn’t.

“Most MPs understand the value of taking a break after the election, and clearly the members care more about getting the best candidate rather than the one who did the most media in August. In the only truly independent poll by YouGov Kemi was the outright leader by a distance.”

In that poll of Tory members, carried out a week ago, Badenoch had the backing of 24%, with Tugendhat second on 16%, Cleverly on 14%, Jenrick on 12%, Patel on 11% and Stride on just 2%.

Nevertheless, Jenrick – viewed as Badenoch’s main rival in the battle to be the standard bearer for the Tory right – has won plaudits among MPs for his campaign so far.

“I think Rob has got off to the best start, but it’s a long race,” said one backbencher.

“He’s definitely run the most professional, switched-on campaign, there’s no doubt about that.

“I would say at this moment, he is the frontrunner of six. But of course, that doesn’t mean he would be the frontrunner if he makes it to the final two.”

The five who survive the first ballot on Wednesday will be reduced to four in another ballot of Tory MPs the week after.

They will then take part in a leadership beauty contest at the party’s annual conference in Birmingham at the end of September, after which MPs will whittle them down to the final two, with Tory members then having the final say on who should be the party’s new leader.

He or she will be announced on November 2, after which they will take on the Herculean task of trying to take the Conservatives back to power in 2029.

Whoever is chosen to succeed Rishi Sunak will be tasked with turning the Conservatives into a united, competent opposition who can convincingly present themselves to voters as a coherent, alternative government in five years’ time.

The evidence of the last few years, in which the warring party has burned through four leaders and suffered its worst ever election defeat, suggest the chances of success are remote.

But one Badenoch backer told HuffPost UK: “I actually think the leadership contest so far has been quite a civil affair, which suggests that the party is ready to finally come together whoever wins. But time will tell.”