One of Keir Starmer’s closest aides has declined to say whether he would lead his party into the next election amid mounting calls for him to resign.

The prime minister is “listening to colleagues” who are asking him to set out a timetable for departure but would make his own decisions about the way forward, the prime minister’s chief secretary has said.

Darren Jones, a close ally of Starmer, warned the prime minister’s rivals that it was a “gruelling job”, saying: “Anybody who thinks that they can just walk into the job of prime minister and, like the second coming of the messiah, fix all of our problems probably hasn’t really thought carefully enough about how difficult it is.”

More than 70 Labour MPs have publicly called for Starmer to stand down after dire election results across England, Wales and Scotland last week.

Asked if Starmer would be leading Labour into the next election, Jones said: “I’m not going to get ahead of any decision that the prime minister may or may not take.

“He was very clear yesterday that he will not be walking away, as some of my colleagues have asked him to do. We’ve got over 400 Labour MPs in the House of Commons. I think there are now 70 who have raised concerns publicly.”

The Guardian understands that four senior cabinet ministers – Shabana Mahmood, the home secretary, Yvette Cooper, the foreign secretary, John Healey, the defence secretary, and the deputy prime minister, David Lammy – were among those who spoke to Starmer on Monday.

Some told the prime minister he should oversee an orderly transition of power after crushing election defeats risked ringing the death knell on his premiership.

Others discussed with Starmer how they should take a “responsible, dignified, orderly” approach to what may follow. Several others –including Richard Hermer and Steve Reed – were defiant, urging him to fight on.

Jones told Times Radio that most MPs wanted to focus on using the time in government to deliver Labour’s policies. “We have to work together then as a party in this new political era of five-party politics, of the rise of populist parties in our country, to be able to set the course for winning that next election.”

Asked if the king’s speech would still happen on Wednesday, he told Sky News: “Yes, as far as I’m aware, the king’s speech is going ahead tomorrow.

“We’ve been working very hard to bring together a programme of bills for the next session that meet the challenges that we face as a country and it’s important that we get on with that work.”

The cabinet will meet later on Tuesday morning, Jones said. “He obviously will be in conversations with colleagues because of the issues that they have raised, but he was very clear with himself and with all of us that this morning we would be getting on with the job, and I think that’s the right thing to be doing.”

He continued: “Obviously, colleagues are asking the prime minister to consider different options in the future. And, as I say, he rightfully is listening to them. It would be wrong if he wasn’t listening to them.”

In a speech earlier on Monday, Starmer said he would not resign and would prove his doubters wrong, and would fight any leadership challenge.

“I take responsibility for not walking away, not plunging our country into chaos, as the Tories did time and again, chaos that did lasting damage to this country. A Labour government would never be forgiven for inflicting that on our country again,” he said.

Overnight, some Labour MPs began to voice public support for the prime minister. One, Neil Coyle, said: “Horrified at the elephant trap colleagues are falling into. Those who claimed council elections were about Keir had nothing to offer local communities.”

Another, Nick Smith, said. “A global security crisis and its economic impact on our country means we need political stability. Unity is strength.”