LONDON: The ringleader of the July 7, 2005 suicide bombings on London's transport system received advice from a mystery figure in Pakistan just days before the attacks, an inquest heard Wednesday.

Mobile phone records showed a series of calls made from phone boxes of Rawalpindi to bomber Mohammad Sidique Khan, a police officer told hearings in London into the deaths of 52 people.

Metropolitan Police detective Mark Stuart said many of the calls were made through different Pakistani phone boxes within minutes of each other, suggesting that the caller there wanted to conceal their identity.

Hugo Keith, counsel to the inquests, asked Stuart: “Did you assess that those calls therefore were probably connected to some guidance or some means of communicating information concerned with the manufacture of the bombs and then ultimately their detonation?” “Yes, I think they had to be,” replied Stuart.

The inquest heard that Khan never made any calls to Pakistan himself, but that he had instead given contacts in that country the numbers of four phones used purely for the purpose of the attacks.

Most of Khan's conversations with the unknown person in Pakistan took place between May and June 2005 but one lasting six minutes happened five days before the bombings, the inquest heard.

The final, unanswered call to the phone was made on the afternoon of July 7 after Khan, 30, Shehzad Tanweer, 22, Hasib Hussain, 18, and Jermaine Lindsay, 19, had blown themselves up on three subway trains and a bus.

Khan and Tanweer are both known to have travelled to Pakistan in the months before the attack where they are believed to have had contact with members of Osama bin Laden's Al-Qaeda network.

A video statement by Khan is believed to have been filmed there.

Britain's domestic security service MI5 has admitted it monitored Khan on several occasions before the attacks, including meeting members of a separate bomb plot, but that it failed to follow up the lead.

Britain opened the long-awaited inquests into the deaths of the victims in October and the hearings are expected to last until March. They will examine whether the intelligence services could have prevented the attacks.