Saudi Arabia's rulers threatened to make it easier for terrorists to attack London unless corruption investigations into their arms deals were halted, according to court documents revealed yesterday.

Previously secret files describe how investigators were told they faced "another 7/7" and the loss of "British lives on British streets" if they pressed on with their inquiries and the Saudis carried out their threat to cut off intelligence.

Prince Bandar, the head of the Saudi national security council, and son of the crown prince, was alleged in court to be the man behind the threats to hold back information about suicide bombers and terrorists. He faces accusations that he himself took more than £1bn in secret payments from the arms company BAE.

He was accused in yesterday's high court hearings of flying to London in December 2006 and uttering threats which made the prime minister, Tony Blair, force an end to the Serious Fraud Office investigation into bribery allegations involving Bandar and his family.

The threats halted the fraud inquiry, but triggered an international outcry, with allegations that Britain had broken international anti-bribery treaties.

Lord Justice Moses, hearing the civil case with Mr Justice Sullivan, said the government appeared to have "rolled over" after the threats. He said one possible view was that it was "just as if a gun had been held to the head" of the government.