Sir Keir Starmer has said he was "heavily focused" on world affairs before he was forced to U-turn on his welfare bill after rebellion by MPs.
In a piece in The Sunday Times, Sir Keir 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.
His "full attention really bore down" on the welfare bill on Thursday, he added.
It comes after the government was forced to U-turn on plans to cut sickness and disability benefits after significant rebellion by Labour MPs earlier this week.
The government has since offered concessions ahead of a vote in the Commons on Tuesday, including exempting existing Personal Independence Payment claimants (PIP) from the stricter new criteria, while the universal credit health top-up will only be cut and frozen for new applications.
Sir Keir defended the U-turn by saying: "Getting it right is more important than ploughing on with a package which doesn't necessarily achieve the desired outcome."
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.
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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."
Sir Keir said on Saturday that fixing the UK's welfare system is a "moral imperative".
Speaking at Welsh Labour's annual conference in Llandudno, North Wales, Sir Keir said: "Everyone agrees that our welfare system is broken, failing people every day.
"Fixing it is a moral imperative, but we need to do it in a Labour way, conference, and we will."
(c) Sky News 2025: Starmer says he was 'heavily focused' on world affairs before U-turn on welfare bill
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