Boris Johnson appeared rattled on Thursday when faced with further questions over being fined by police for breaking lockdown rules.
It came as a senior Tory and former ally used a speech in parliament to call for the prime minister to resign.
MPs look set to launch a fresh inquiry into whether Johnson misled parliament when he said no Covid laws had been broken during lockdown.
Despite his many denials, Johnson was issued with a fixed-penalty notice (FPN) for attending his own birthday party in the Cabinet Room of No.10 on June 2020.
Johnson had initially tried to delay the new investigation but backed down in the face of opposition from Tory backbenchers.
Speaking to Sky News in India, Johnson said he had “nothing, frankly, to hide” from another inquiry.
And he insisted the Conservative Party would let him lead them into the next general election.
Pushed on whether the current situation he finds himself in was serious, the PM replied: “Of course, I think it is serious.
“I also think we have massive issues that people expect us to address. I think people want us to get on with the job of taking the country forward,” he said.
But he appeared frustrated with the line of questioning, asking “how many” times Sky’s political editor Beth Rigby would press him on partygate.
“You promised to get on, you did promise to get onto the substance of this trip?” he said, having checked his watch and looked at the sky in irritation.
“Well come on,” Johnson told Rigby when she said there would also be questions about a potential trade deal between the UK and India.
As MPs debated whether to ask the privileges committee to investigate whether Johnson lied to parliament, Steve Baker said the PM should be “should be long gone”.
Baker, a former Brexit minister, is a prominent Brexiteer and was involved in ousting Theresa May.