Irish dissidents issue bomb warning for London
16 May 2011 Last updated at 19:45 BST
A bomb threat for London has been issued by Irish dissidents in the first coded warning outside Northern Ireland in 10 years, officials say.
Streets around the Mall were closed for five hours on Monday morning amid a major security alert.
Whitehall officials said the call with the coded warning came from a number in the Irish Republic on Sunday evening.
The threat level for Northern Ireland-related terrorism, which stands at severe, has not been changed.
Gordon Corera reports.