The IRA is believed to have kept secure much of its arsenal since it announced the second ceasefire in 1997, though some of it was secreted away following a split in the ranks that year.

THE homemade explosive thought to have been used in both London bombing waves can deteriorate after just a few days.

OSMIUM TETROXIDE is the chemical believed to be at the centre of an alleged bomb plot foiled by ‘British and American intelligence agents.