UK Minister for Middle East and North Africa James Cleverly said Israel's plans to annex the West Bank are "contrary to international law".
When asked by Scottish National Party MP Tommy Sheppard if the UK government would consider the move "illegal under international law", Cleverly said that attempting to annex the West Bank would make a two-state solution difficult to achieve, in a break with UK support of US foreign policy.
He told parliament: "Our long-standing position is that we do not support the annexation of parts of the West Bank, and … doing so could make a sustainable two-state solution harder."
The UK government has previously expressed concern over Israeli annexation plans.
Foreign Secretary Dominic Raab said in January: "The United Kingdom is concerned by reports of possible moves toward annexation of parts of the West Bank by Israel."
On Monday, a cross-party Early Day Motion (EDM) sponsored by Conservative MP Crispin Blunt and Labour MP Andy Slaughter, and signed by 40 MPs, called on the government to make clear there would be "severe consequences" for Israel's relationship with the UK if the annexation plan went ahead.
The EDM called on the government to "make clear to the Israeli Government that such a step will have severe consequences for the UK-Israel relationship; and further calls on the Government to introduce sanctions similar to those imposed on Russia [for its annexation of Crimea] in the event that an annexation of occupied territory takes place."
US Secretary of State yesterday gave Israel the green light on its plans to annex the illegally occupied Palestinian territory.
The US in the past has supported Israeli annexation of illegally occupied territory. President Donald Trump in March 2019 signed an executive order recognising Israeli sovereignty over the occupied Syrian Golan Heights in a joint ceremony with Israeli Prime Minister Benjamin Netanyahu.
The United Nations was quick to condemn the move, declaring the Golan Heights illegally occupied under international law, despite the executive order.