The British Home Secretary, John Reid, has said Britain's security level remains 'critical' following yesterday's arrests of 24 people who had allegedly plotted to blow up aircraft bound for the United States.
Delays at airports are beginning to ease although major security checks remain in place with a high police presence at all British airports and train stations.
Dr Reid told a news conference today that authorities were confident that all the main suspects were in custody, but said that he could not give a guarantee.
He was responding to reports from the US which claim that as many as five leading figures in the alleged plot have escaped the police net.
Nineteen of those being held in connection with the alleged plot have had their assets frozen. All have been named publicly by the Bank of England.
Pakistan has said it arrested two UK citizens eight to ten days ago in connection with the plot. It had earlier been reported that Pakistan arrested at least three men.
Pakistan said the plot was foiled after active coordination between Pakistani, British and US intelligence agencies.
Heavy delays on US flights at Heathrow
Meanwhile, most inbound flights to London's Heathrow Airport are arriving on time, although flights from the US are heavily delayed.
Most flights to and from Irish airports are operating normally, but passengers to the US are still being told not to pack liquids or gels in their hand luggage.
Dublin Airport Authority is advising that passengers are allowed to carry one piece of hand luggage on flights to the UK but that passengers on flights departing any UK airport cannot bring any hand luggage.
The Irish Government is continuing to monitor developments in the UK.
Speaking on behalf of the Government, Junior Minister Brian Lenihan said security officials are keeping a very close eye on the situation.
The National Security Council and the National Civil Aviation Security Committee both met in the wake of yesterday's events.
