The information commissioner is to launch an investigation after a complaint by a campaign group that forces at the US’s largest eavesdropping centre in Britain are breaking the law.

Reprieve said US forces at Menwith Hill in North Yorkshire were failing to comply with the provisions of the UK Data Protection Act by collecting and processing personal data without registering with the information watchdog.

Drawing on reports about how US surveillance operations identified targets for drone strikes, the charity said personnel at the base operated programmes that monitored and located communications, including mobile phone calls and wifi traffic.

In a letter to the Information Commissioner’s Office (ICO), Reprieve detailed the experience of the al-Manthari family in Yemen, who were caught up in a March 2018 US drone strike. While the US claimed the strike had killed members of al-Qaida, Reprieve alleges that its investigations revealed all the victims were civilians.

“We write to ask you to investigate this as a matter of urgency, given that individuals’ lives may be at stake,” Reprieve said in its letter to the ICO.

An ICO spokesperson said: “We will consider the complaint but it will be important to establish the arrangements the UK government has made with other sovereign states for operating out of bases in the UK and the applicability of UK law to their activities on that base.”

Jennifer Gibson, who leads Reprieve’s investigations into the use of drones and other forms of lethal force outside of war zones, said: “The government guarantees us that US activities at RAF Menwith Hill are carried out with their knowledge and consent.

“Yet the Trump administration is openly flouting UK law by not registering with the Information Commissioner’s Office. That they feel they can ignore such a basic requirement raises the question of what other British laws they are breaking.”

A spokesperson for the Ministry of Defence said: “RAF Menwith Hill is part of a worldwide US defence communications network, with the base supporting a variety of communications activity.

“US forces maintain robust civilian and military cooperation with the United Kingdom and manage all base activities in accordance with the agreements made between the United States and Her Majesty’s government.”