Pakistan has asked the United Kingdom whether it was Prime Minister Tony Blair who personally authorised the bugging of its high commission in London.

Diplomatic sources in London confirm that Britain's High Commissioner to Islamabad, Mark Lyall Grant, was summoned to the foreign ministry and asked how and why electronic surveillance devices were planted inside the lavish mission.

This follows last weekend's revelations that during extensive refurbishments carried out in the building in 2001, UK security agents planted bugging devices inside closed-circuit television units, within the internal telephone service and elsewhere inside the mission's premises.

Pakistan wants to know if the surveillance measures were conducted by so-called rogue elements within the UK security services, or whether they were backed by the Blair government.

It was the UK's prestigious Sunday Times newspaper that exposed the bugging operation last weekend. Although the paper did not specify the mission involved, the game was given away by a number of vital clues, including a description of the naval attaché's office on the top floor of the building and the visa office in the basement.

Rediff.com has learnt that the head of Britain's internal security service MI15, the equivalent of the IB, personally telephoned the newspaper last Saturday night in a bid to stop the story's publication.

The operation has invoked memories of diplomatic exchanges between the West and the Soviet Union and its allies.

Less than 20 years ago Western and Soviet diplomats stationed in each other's capitals routinely assumed they and their homes and offices were under constant surveillance.

But Pakistan in British eyes is officially deemed a friendly Commonwealth country and ally, albeit one that is ruled by a military dictator, and not subject to what can be perceived as hostile screening.

The decision to turn the spotlight on Pakistan seems to have been prompted by concern that some UK-based Islamic radicals of Pakistani origin have joined the Al Qaeda, either in the border regions of Afghanistan or other conflict hotspots in West Asia.

In its article the paper says the task of facilitating the bugging operation was given to a former MI5 agent, codenamed Notation, who has since confessed his role to the high commission. "It is likely that the foreign office will now have the embarrassing task of explaining the espionage operation to its ally," the article says.

It further claims that MI5 took detailed plans and photographs of the diplomatic mission before working out how to plant bugs in the internal telephone system and inside a closed-circuit television camera in the office of a diplomat. One officer is even alleged to have pretended to be carrying out a search for hazardous materials to gain access to secure areas.

Meanwhile agent Notation received tens of thousands of pounds as cash payment from MI5. He was, according to the Sunday Times, also told by his handlers that the entire operation had been authorised at the highest level with warrants being signed by Home Secretary David Blunkett.