Sir Keir Starmer has said he did not get to grips with the growing rebellion over welfare reforms earlier as he was focused on international affairs.
He also said he took ownership for his decisions and believed as leader he should “carry the can” when things do not go well.
The Prime Minister said he was occupied with the G7 and Nato summits and the escalating tensions in the Middle East for much of the past two weeks.
He said he was “heavily focused” on what was happening with Nato and the Middle East all weekend and that his “full attention really bore down” on the welfare bill on Thursday.
He defended the eventual U-turn, which came after more than 100 MPs launched a bid to kill the legislation with an amendment.
“Getting it right is more important than ploughing on with a package which doesn’t necessarily achieve the desired outcome,” Sir Keir told The Sunday Times.
He said all the decisions were his and that “I take ownership of them”.
There have been reports that rebel MPs blamed Sir Keir’s chief of staff Morgan McSweeney for the Government’s approach.
Sir Keir said: “My rule of leadership is, when things go well you get the plaudits; when things don’t go well you carry the can.
“I take responsibility for all the decisions made by this government. I do not talk about staff and I’d much prefer it if everybody else didn’t.”
Ministers had hoped the reforms would get more people back into work and save up to £5 billion a year, but the concessions made leave Chancellor Rachel Reeves needing to find money elsewhere and point to possible tax rises in the autumn.
On Saturday, the Prime Minister told the Welsh Labour conference the “broken” welfare system must be fixed “in a Labour way”.
He said: “We cannot take away the safety net that vulnerable people rely on, and we won’t, but we also can’t let it become a snare for those who can and want to work.”
Conservative Party leader Kemi Badenoch will hit out at Sir Keir as “incapable of sticking to a decision” after he backed down on his plans.
The reforms would only have made “modest reductions to the ballooning welfare bill”, but the Prime Minister was “too weak to hold the line”, the Conservative Party leader is expected to say in a speech next week.
The Government’s original welfare package had restricted eligibility for Pip, the main disability payment in England, as well as cutting the health-related element of universal credit.
Existing recipients were to be given a 13-week phase-out period of financial support in an earlier move that was seen as a bid to head off opposition.
Now, the changes to Pip will be implemented in November 2026 and apply to new claimants only, while all existing recipients of the health element of universal credit will have their incomes protected in real terms.
The concessions on Pip alone protect some 370,000 people currently receiving the allowance who were set to lose out following reassessment.
As a year in office nears, more than half of voters think Labour has underperformed in that time, polling released on Saturday showed.
The Opinium survey showed 54% think Labour has done a worse job than expected, while 18% think the party has exceeded expectations.
