When international pressure mounted on Pakistan after the 2001 attack on India’s Parliament and the finger of blame was pointed to the LeT, the Pakistani security establishment told Western nations, including the US and Britain, that it would keep a tight check on the group as it could not be wound up, diplomatic sources said.

“The Western powers were told that the LeT had an extensive network within Pakistan and any effort to root it out could lead to massive security problems within the country. Thus it would not be possible to wind up the group,” a diplomatic source, who was aware of details of the assurance given by Pakistan’s security set-up to countries like Britain, told PTI.

“The Western countries were told that the security establishment would instead establish a cordon sanitaire around LeT camps. So even if people were still training within these camps, they would not be able to move about freely to carry out attacks anywhere,” the source said.

As Indian and Western intelligence agencies gathered evidence after the Mumbai attacks that showed the assault on India’s financial hub was masterminded and coordinated by LeT operatives, including its operations commander Zakiur Rehman Lakhvi, the Western powers were convinced that Pakistan’s security establishment had not delivered on its assurance. Britain, in particular, used this issue to pressurise Pakistan to take action against the LeT, the sources said.

Both British Prime Minister Gordon Brown, who said 75 per cent of terror plots investigated by UK had links to Pakistan, and Foreign Secretary David Miliband are believed to have taken up the issue during their visits to the country.

Preliminary investigations into last week’s Lahore attack have also suggested that the assault was the handiwork of a group of LeT operatives.