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.
Israel's latest ground operation in Gaza City, described by a UN official as cataclysmic, has forced hundreds of thousands of people to flee.
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.
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.
While Conservative leader Kemi Badenoch expressed the desire for a two-state solution, she emphasized in The Telegraph that recognition of a Palestinian state at this time, before the release of hostages taken by Hamas, would be considered a reward for terrorism.
Furthermore, family members of hostages have urged the Prime Minister not to proceed with the recognition until the remaining hostages are returned.
The announcement, scheduled to coincide with the upcoming UN General Assembly meeting, underscores growing pressures on the UK government to adopt a firmer stance on Israel amidst worsening conditions in Gaza.
Recognising a Palestinian state aligns with recent actions by other nations, with countries like Portugal, France, Canada, and Australia also affirming Palestinian statehood. Currently, Palestine holds recognition from around 75% of UN member states despite lacking internationally agreed boundaries or a capital.
This shift in British policy has become crucial amid calls from Labour MPs for immediate recognition as a means to revitalize the peace process in the region.