It came amid reports that Peru's army had launched an operation to remove some 300 Shining Path rebels who work closely with cocaine traffickers in the region.

BBC: Peru rebels launch deadly ambush

MI5 soon discovered that the two main instigators of the successful attack, Mohammad Sidique Khan and Shehzad Tanweer, had crossed their path before, particularly on the fringes of Operation Crevice.

ECONOMIST: Waiting for al-Qaeda's next bomb

But now, thanks to strict regulations and international co-operation, the river is on the path to recovery.

BBC: Rhine on path to recovery