Pakistan has rejected Britain’s request to question suspects arrested in connection with last month’s Mumbai attacks, Yousuf Gilani, the Pakistani Prime Minister, announced last night in a blow to international efforts to investigate the atrocity.

Gordon Brown made the request in meetings with Pakistani leaders in Islamabad on Sunday after visiting India earlier in the day to try to ease tension between the nuclear-armed neighbours.

Mr Brown demanded “actions, not words”, blaming Pakistani militants for the Mumbai attacks and revealing that three quarters of the gravest terror plots under investigation in the UK had links to Pakistan.

However, Mr Gilani turned down his request for British police to interview any of the suspects who have been arrested since Pakistan bowed to international pressure to crack down on militant groups last week.

“Prime Minister Yousuf Raza Gilani said that in his meeting on Sunday with the British Prime Minister, he turned down his request for Britain probing the Pakistanis detained after (the) Mumbai attacks,” Mr Gilani’s office said. “He said he told Gordon Brown that if there were any proofs, these persons will be prosecuted under the law of Pakistan.”

A spokesman for the Foreign Office said that it was up to India and Pakistan to investigate the Mumbai attacks “to ensure that those responsible for these heinous crimes are held accountable.” “We will continue to offer what support we can, including police expertise, but we will not impose it,” he told The Times.

Pakistan’s response is, however, a blow for British police and intelligence officers, who had been hoping to glean valuable information about the Mumbai attacks and about terror networks operating in the UK.

It also represents a setback for India, which wants the United States and Britain to help prove that militants with links to Pakistan’s intelligence service carried out the Mumbai attacks.

Indian, US and British intelligence agencies have all blamed the attacks on Lashkar-e-Taiba, a Pakistani militant group that was banned here in 2002 but continues to operate underground and is believed to have links to Britain.

Pakistan arrested dozens of suspected LeT militants last week and closed down some of the offices of Jamaat-ud-Dawa, a charity led by the LeT’s founder, after it was added to a UN terrorist list on Wednesday.

However, Pakistan has refused to extradite the suspects to India and offered instead to try them on its own soil if there was evidence against them.

Asif Ali Zardari, Pakistan’s President, told Mr Brown on Sunday that his government had no evidence that the Mumbai attacks were carried out by Pakistani militants.

Mr Brown had offered Mr Zardari an additional £6 million in security assistance, urging Mr Zardari to “break the chain of terror” linking Islamist militants in Afghanistan and Pakistan to attempted terrorist attacks in Britain.

British military officials believe there are a “handful” of British militants fighting alongside the Taleban in Afghanistan, often entering the country through Pakistan.

Officials also believe that there are currently around 30 major terrorist plots in the United Kingdom with 2,000 suspects being watched by police and the intelligence services.

Mr Brown did, however, secure permission from India for British police to interview the only surviving militant from the Mumbai attack to investigate whether he has British connections.

Manmohan Singh, the Indian Prime Minister, gave the go-ahead for police and intelligence officials to speak to Mohammed Ajmal Amir Qasab, who has been undergoing “sustained interrogation” in a Mumbai jail since being captured on the first day of the attack.

Two police officers from Scotland Yard flew out to Mumbai during the attacks as part of a rapid deployment team, including Foreign Office and Red Cross staff. The police officers have since been replaced by others, but none has had access to Mr Qasab or to the attack sites so far, according to the British High Commission in Delhi.

Scotland Yard confirmed that its officers were still in Mumbai to support the Indian investigation, but declined to give any further details.

Analysts say US and British security officials are keen to get more actively involved to glean potentially valuable intelligence and to help ensure that India gathers solid evidence against Pakistani militants.

Indian police have a long history of blaming Pakistan for terrorist attacks on its soil and leaking purported evidence to the Indian media, but never doing thorough forensic evidence or presenting proof to Pakistani authorities.

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