By politics.co.uk staff
Irish republican dissidents are thought to be behind a bomb threat against central London made last night, according to reports.
The Metropolitan police said the threat did not offer a specific location or time and advised Londoners to continue to go about their business as usual.
Areas of the Mall were cordoned off this morning for several hours, however, as part of broader increased police activity.
"The Metropolitan Police Service, City of London police and British Transport police are working closely together and all officers have been advised to be a highly vigilant to ensure the safety of London," the Met said in a statement.
"Policing operations and contingency planning remain under constant review and a wide range of overt and covert tactics will continue to be used in London."
Last September the threat level from Irish-related terrorism was increased from 'moderate' to 'substantial', meaning an attack is a strong possibility.
This remains lower than the overall threat to the UK from international terrorism, however, which remains at 'severe'.
Police have appealed to members of the public to be vigilant and report any unusual activity or behaviour to the anti-terrorist hotline on 0800 789 321.