Conservative MPs should not change the rules to allow another confidence vote in the prime minister within a year, Sajid Javid has said.

The health secretary said it was a “clear and decisive result” on Monday night when Boris Johnson won a confidence vote among his MPs – although 148 voted against him.

There have been suggestions the 1922 Committee of backbench Tory MPs could change the rules that currently state another confidence vote in a leader cannot happen within a year after they have won a ballot.

Rebel MP Tobias Ellwood told Sky News on Tuesday he believes the committee is looking into changing the rules so the PM could face another vote in six months.

But Mr Javid told Sky News’ Kay Burley: “Of course, they shouldn’t change the rules.

“There’s no need to change any rules because we’ve had the ballot, it’s a clear, decisive result.

“And we’ve just got to get on with the job.”

MPs unhappy with Mr Johnson can hand in letters of no confidence to the 1922 Committee chair Sir Graham Brady, and on Monday he announced the threshold of 15% of Tory MPs – 54 – had done so, which triggered the vote.

Speculation has risen in the wake of Monday’s vote, with an “influential” rebel telling The Times a “majority of 1922 officers” will agree to change the rules “when the time is right” – and they expect that to happen before the party conference in October.

But Tory MP Karl McCartney, who is on the 1922 Committee, said the 16 MPs on the executive “have never discussed changing the rules” and that speculation is “nonsense”.

A source close to the 1922 Committee told Sky News a rule change was expected to be discussed at their meeting this week but they do not think it will happen.

“You can’t do this once the year has started. You could have done it before the vote or after the year is up but I can’t see how you can change the rules mid-game,” they said.