Sir Keir Starmer is expected to announce the UK's recognition of a Palestinian state in a statement on Sunday afternoon.
The move comes after the prime minister said in July the UK would shift its position in September unless Israel met conditions including agreeing to a ceasefire in Gaza and committing to a long-term sustainable peace deal that delivers a two-state solution.
It represents a major change in British foreign policy after successive governments said recognition should come as part of a peace process and at a time of maximum impact.
The move has drawn fierce criticism from the Israeli government, hostage families and some Conservatives.
Israeli Prime Minister Benjamin Netanyahu previously said such a move rewards terror. However, UK ministers argue there was a moral responsibility to act to keep the hope of a long-term peace deal alive.
Government sources said the situation on the ground had worsened significantly in the last few weeks. They cited images showing starvation and violence in Gaza, which the prime minister has previously described as intolerable.
Earlier this week, a United Nations commission of inquiry concluded Israel had committed genocide against Palestinians in Gaza, which Israel denounced as distorted and false.
Ministers also highlighted the continued expansion of Israeli settlements in the occupied West Bank, which are illegal under international law, as a key factor in the decision to recognise Palestinian statehood.
Justice Secretary David Lammy, who was foreign secretary in July when the path to recognition was announced, cited the controversial E1 settlement project which critics warn would put an end to hopes for a viable, contiguous Palestinian state.
He said: The recognition of a Palestinian state is as a consequence of the serious expansion that we're seeing in the West Bank, the settler violence that we're seeing in the West Bank, and the intention and indications that we're seeing to build for example the E1 development that would run a coach and horses through the possibility of a two-state solution.
Palestinian Authority president Mahmoud Abbas welcomed the UK's recognition pledge when he visited Sir Keir earlier this month, with Downing Street saying both leaders had agreed Hamas had no role in future governance of Palestine.
However, critics, including Conservative leader Kemi Badenoch and families of hostages taken by Hamas, argue that this recognition should not occur until hostages are released and call it a reward for terrorism.
The UK government faces increasing pressure both from within and internationally to respond effectively to the deteriorating conditions in Gaza and to ensure a pathway to peace that includes all stakeholders.
