LONDON — Acting on intelligence failures exposed by the attempted bombing of a Detroit-bound airliner on Dec. 25, Prime Minister Gordon Brown announced a major tightening of British aviation security measures on Wednesday, including the creation of a new no-fly list of terrorist suspects similar to one maintained by the United States.

Mr. Brown announced an immediate suspension of the twice-a-week flights between London and Sana, the capital of Yemen, by Yemen’s national airline, Yemenia, while efforts are made to improve airport security in Yemen. A new focus on Yemen as a base for plots by Al Qaeda has been one of many consequences of the failed Dec. 25 attack. American authorities have accused a 23-year-old Nigerian, Umar Farouk Abdulmutallab, and say he was prepared for the plot by Qaeda operatives in Yemen.

After President Obama chastised American intelligence agencies for failing to piece together information about Mr. Abdulmutallab in time to prevent him from boarding the Amsterdam-to-Detroit flight, attention turned to British intelligence agencies. American officials faulted the British for their failure to notify them that the Nigerian, known to British agencies for his contacts with Islamic extremists during three years of university studies in London, had been refused a visa to re-enter Britain last May.

The most important of the new British measures announced by Mr. Brown in a statement to the House of Commons involved what he described as an extension of the country’s terrorist watch list to include people who have shown up during surveillance operations but were not previously considered sufficient threats to make the list. Along with this, he said, Britain planned to “improve the sharing of information on individuals of concern” with foreign security agencies. Both measures appeared to have been motivated by Britain’s failure to alert American agencies to Mr. Abdulmutallab as a potential threat.

Underlining the importance Britain attaches to its intelligence relationship with the United States, and to repairing any damage done by the failure to pass information to American agencies about Mr. Abdulmutallab before the Detroit flight, Mr. Brown said he had briefed Mr. Obama about the measures in a conference call on Tuesday, one of several that have taken place between the men since the attack.

Mr. Brown said that Britain’s expanded watch list would be used as the basis for the new no-fly list, the nation’s first, which would prevent anybody listed from boarding a flight to Britain, or transiting through Britain to other destinations, including the United States. The list appeared to be similar to one maintained by the Department of Homeland Security in the United States, which lists more than 4,000 people who are barred from boarding flights to the United States.

Failure to place Mr. Abdulmutallab on the United States list after his father warned United States Embassy officials in Nigeria about his son’s increasingly radical Islamic views — and after United States agencies detected signs that a Nigerian was being prepared for a suicide bombing in Yemen — formed the background to Mr. Obama’s criticism of American intelligence failures.

Mr. Brown said he had also briefed Mr. Obama about other measures Britain was taking to improve aviation security, including installation of body scanners that will go into operation next week at airports including Heathrow in London; an increase in “explosive trace testing” of checked and carry-on baggage; and wider use of sniffer dogs. In addition, he said, Britain will be demanding “greater guarantees about security” at all international airports with flights to Britain.

Mr. Brown’s statement reflected the wide ramifications for Western intelligence agencies of the failed bombing attempt last month. Mr. Abdulmutallab, the chief suspect, is the only one charged so far. He is accused of trying to destroy a Northwest Airlines jet with nearly 300 passengers and crew members. Federal prosecutors say the young Nigerian came within a hair’s breadth of downing the aircraft by igniting explosives sewn into his underwear.

British officials have attributed their failure to tell the United States what they knew about Mr. Abdulmutallab to the suspect’s own seemingly peripheral contact with Islamic extremists, saying he was not considered a terror threat himself. They have said that the 2009 visa refusal resulted from the Nigerian’s application to register at a “bogus college” not on a visa-approval list, an action that placed him in a pool of thousands of rejected applicants, but not on a Home Office watch list of potential terrorists requiring notification of United States agencies.

Although Mr. Brown stopped short of acknowledging that Britain’s failure to pass information about Mr. Abdulmutallab to the United States might have played a part in the Detroit attack, he left no doubt that Britain’s new measures were aimed, in significant measure, at quieting American concerns. Even before the Detroit attack, American officials complained privately about what they described as Britain’s failure to act decisively against Islamic extremists who pose a threat to the United States.

The case most often cited involved a plot to use explosives hidden in soft-drink bottles to bomb seven or more North America-bound airliners departing from London on a single day, which was uncovered, partly due to American intelligence efforts, in 2006. After two trials, three British Muslim men were sentenced last year to life imprisonment for their roles in the plot.

For their part, British intelligence officials have said that they view American criticism as part of an effort to deflect responsibility for American failures identified by Mr. Obama. They have responded by citing the broad efforts Mr. Brown referred to in his Commons statement to expand Britain’s counterterrorism capabilities since the 9/11 attacks in the United States, including a tripling of the budget for the country’s domestic security agencies; a doubling of the staff in the two main security agencies, MI5 and MI6; and new antiterrorism laws.

http://www.nytimes.com/2010/01/21/world/europe/21britain.html?ref=todayspaper&pagewanted=print

Copyright 2010 The New York Times Company