Shadow home secretary James Cleverly has said he will not accept a frontbench role from the next leader of the Conservative Party, after they are unveiled on Saturday.

The winning candidate – Kemi Badenoch or Robert Jenrick – is likely to carry out an immediate reshuffle of the Tory frontbench team.

But Cleverly has told the Financial Times (FT) he will return to the backbenches rather than serve in either candidate’s shadow cabinet.

Following the Tory conference, Cleverly briefly became the frontrunner in the race to replace Rishi Sunak, but was surprisingly knocked out in the final ballot of MPs.

He told the FT he had been “liberated” from 16 years on the political front line and was now “not particularly in the mood to be boxed back into a narrow band again”.

Cleverly shot to the front of the pack of leadership candidates after a well-received speech to the Conservative conference early last month, in which he called for the party to be “more normal” and sell its policies “with a smile”.

However, his support unexpectedly fell away in the last round of MPs’ voting.

Many theories were advanced on why that had happened, including that some of his supporters had tried to engineer the final line-up they wanted.

The former home and foreign secretary was eliminated with 37 votes. Badenoch secured 42 and Jenrick 41.

There were gasps in the Commons committee room where the result was announced.

Cleverly admitted to the FT the result was a “bit of a punch to the gut”, saying he had repeatedly warned his backers that “Kremlinology is a fool’s game” – but that he “lost track” of the number of supporters who asked who he would prefer to go up against.

“I’d worried that that might happen,” he said, adding: “I kept saying there aren’t many votes to play with… it doesn’t take very many people to really distort outcomes.”

He declined to say who of the final two he had backed.

When Badenoch and Jenrick topped the MPs’ poll, both signalled they would offer him a position in their shadow cabinet if they became leader.

Badenoch said Cleverly’s campaign had been “full of energy, ideas and optimism”, and she looked forward to “continuing to work with him”.

Jenrick told Cleverly the party “needs you in its top team in the years ahead”, adding that he would be “delighted for him to serve in the shadow cabinet should he want to do so”.

Jenrick has made leaving the European Convention on Human Rights (ECHR) a key plank of his leadership offer, saying all Tory MPs would need to sign up to the policy – but Cleverly has rejected the idea.

However, a stint on the backbenches appears unlikely to last forever and Cleverly has left the door open to a future bid to become leader of the Conservative Party, saying he would not “rule anything in or anything out”.

Nor did he rule out the idea of a bid to become mayor of London in 2028, adding: “We do need to fight back in London. We need to fight back in big, big, big chunks of the country.”