Iran’s Foreign Minister has warned Yvette Cooper in a phone call that allowing US use of UK bases is considered as British “participation in aggression”.

Green MPs and peers have written to Keir Starmer expressing alarm at the UK’s involvement in the illegal US-Israeli war on Iran and pressing the Prime Minister to answer a number of urgent questions – including what control, if any, the UK has over US strikes launched from British bases and whether British-made weapons components are being used in breach of international law.

They note that the UK is obliged under international law to have no involvement in illegal military action, including the use of UK bases and UK-made weapons, and reiterate demands for an end to all UK complicity in this illegal war.

FULL TEXT OF LETTER

Dear Prime Minister, 

We are writing as Green Party MPs and Peers to express our alarm at the UK’s involvement in the illegal US-Israeli war on Iran. 

Already well over 1,000 civilians have been killed, including a reported 168 children killed by a missile now widely believed to be from the United States (Guardian, 2026). UNICEF has reported that the Israeli military’s assault on Lebanon is killing or injuring the equivalent of one classroom of children every day (Reuters, 2026).

In addition to the grave humanitarian impacts, the longer this illegal, unnecessary war continues, the greater the global economic fallout – to which the UK is particularly exposed because it remains heavily reliant on fossil fuels. 

In light of this, there are urgent questions your government must answer: 

• What steps, if any, is your government taking to ensure that B-1 and B-52 bombers taking off from RAF Fairford are being used for ‘specific, limited defensive purposes’ – as you committed to?
• What assessment have you made, if any, of how many Iranian civilians have been killed by US bombing missions from British air bases?
• Are target lists for US strikes from British soil approved by the Ministry of Defence before each mission or audited afterwards? 
• Is the US being permitted to load banned cluster munitions at British bases?
• What assessment has the government made of the risk of UK-made weapons components being used in violation of international law in Iran, including in the Tomahawk missile systems which may have been involved in the strike on the Shajareh Tayyerbeh girls’s school which killed a reported 168 children and 14 teachers, in the single deadliest known attack so far? 
• What assessment has the government made of the risk of UK-made weapons components being used by the Israeli government in violation of international law in Lebanon? 

The UK is obliged under international law to have no involvement in illegal military action, including the use of UK bases and UK-made weapons. It is therefore of the utmost importance that these questions are answered as a matter of urgency. 

This illegal war is inflicting untold suffering and devastation in the region and will cause huge and long lasting human, political, economic and environmental ramifications, as well as the immediate impact on the cost-of-living for our constituents. We, as Green Party MPs and Peers, reiterate our calls for the UK government to: 

• Withdraw all permission for the US to use UK military bases for attacks on Iran.
• End all arms sales to and military cooperation with the Israeli government.
• Impose sanctions on government officials responsible for breaches of international law.
• Condemn the actions of Trump and Netanyahu for their flagrant violations of international law.
• Refuse any further complicity in this illegal war.

Yours sincerely, 

Dr Ellie Chowns MP

Carla Denyer MP

Siân Berry MP

Hannah Spencer MP

Adrian Ramsay MP

Baroness Bennett of Manor Castle

Baroness Jones of Moulsecoomb