Several airports and train stations, including those in London, were placed on high alert on Friday following what officials described as “credible” reports of “intelligence chatter” suggesting Britain's transport hubs could be targets of a terror attack.
The overall terror threat level, however, remained unchanged and security agencies stressed there was no suggestion of an imminent attack.
Airports and train terminals affected by the increased security alert were not named but some were thought to be in London.
The BBC said it had seen a copy of a letter sent from the Department for Transport to aviation officials saying there were indications Al-Qaeda “may be considering an attack against a U.K. airport or aviation sector target”.
Describing the reports as “credible”, the letter said the “economic, political and psychological significance of the U.K. aviation sector, coupled with the large crowds present within some of its major assets, would enable a successful attack to fulfil Al-Qaeda's objectives”.
There has been concern about the possibility of Mumbai-style attacks in Europe and last month a man who had lived in Britain and attended university here blew himself up in Stockholm, barely yards from the Indian embassy. Soon afterwards, 12 men, some of Bangladeshi origin, were arrested in terror raids across Britain on suspicion of planning a terror attack. Three were released and nine charged with a range of terror-related offences.
According to media reports, three men arrested last week in Denmark for allegedly planning an attack on a Danish newspaper which had published Prophet Mohammed's cartoons had links with a U.K.-based terror network run by Ilyas Kashmiri, dubbed the “new” Osama bin Laden.