They are alleged to have plotted with al-Qaeda to carry out the attack in the hope of destabilising the government and paving the way for a military coup.

Prosecutors suspect that the former heads of the air force, navy and Turkish 1st army were linked to attacks on the British consulate, HSBC headquarters and synagogues. Roger Short, the consul general in Istanbul, was killed in the bombing at the consulate in the heart of Istanbul in November, 2003. Lisa Hallworth, from Denton, Greater Manchester, and Nanette Elizabeth Kurma, a former airline worker, from Drongan, Ayrshire, were also killed.

Although a group linked to al-Qaeda claimed responsibility at the time, there have always been questions over its ability to source bomb-making materials and evade security controls in a country with a powerful security force.

Investigators claim the bombings were part of "Operation Sledgehammer" which had been formulated by senior military figures eight months earlier to destabilise Turkey and trigger a military intervention to overthrow the government.

Prosecutors have arrested 35 former military figures in recent weeks on suspicion of being part of the plot, which is also said to have involved plans to provoke Greece into shooting down a Turkish fighter jet.

Turkey's armed forces traditionally view themselves as defenders of the secular state and harbour deep suspicions over the religious origins of the AK Party of Recep Tayyip Erdogan, the prime minister. Gen Çetin Dogan, who has been described as the ringleader of the conspiracy as head of the 1st army and then deputy chief of the military staff, faced questions over the Istanbul bombings before being remanded in custody on Sunday. Gen Ibrahim Firtina, the former air force chief, and Adml Özden Örnek, a former naval commander, also faced questions over links to the Istanbul bombing.

Sixty-nine people were tried in 2006 over the car bombings. DNA tests proved that the driver of the vehicle used to blow up the consulate was Feridun Ugurlu, a militant who had previously been named as an accomplice in the synagogue attacks.

Those responsible for the attacks said it had been carried out in retaliation for Britain's role in the invasion of Iraq in March, 2003.

Canon Ian Sherwood, an Anglican priest whose church was blown up in the attacks, said the report demonstrated the ruthlessness of those allegedly plotting to depose the government.

"We knew that a lot of people had been arrested, gone to court and are in jail over the attacks," he said. "So this is a surprise. We used to think thank God for the army but this shows that fanaticism in secularism is just as bad as fanaticism in religion."

Mr Erdogan yesterday announced he was planning to introduce sweeping changes to the constitution imposed by the military in 1982. The reforms would allow the government to make changes to the judiciary, another bastion of opposition to the AK party.

If military leaders of a prominent Nato ally are implicated in an attack on a British diplomatic post, the ramifications would be far-reaching. "There is a militarist establishment in Turkey, made up not only of soldiers but also judges and prosecutors and others in the bureaucracy," said Sedat Laciner, head of a Turkish-American think tank. "This establishment is no longer able to protect itself."

A Foreign Office spokesman said Britain was not asking for the investigations into the attacks to be reopened.

Damien McElroy

The Daily Telegraph (London)

March 2, 2010 Tuesday