What made the British government think about strengthening security measures?

Sept. 16 (Bloomberg)--Three years after the Sept. 11 attacks in the U. S. , two breaches of security in two days at London’s Buckingham Palace and the Houses of Parliament prompted calls for increased measures to protect the U. K. capital.
   Five protesters yesterday entered the main chamber of the House of Commons as legislators held a debate and on Tuesday a man scaled the wails of Buckingham Palace. The U. K. , which hasn’t suffered a devastating terrorist attack since 29 people died in the Real IRA’s August 1998 Omagh bombing, is among countries that should revise their approach to security, a study commissioned by the European Union said yesterday.
   While Britain has made progress, the incidents "highlight complacency and show that we still have a long way to go," said Sandra Bell, head of homeland security at the Royal United Services Institute, which analyzes security and defense issues. The U.K. needs to work on the "tools and technology" it uses to fight terrorism, she said in a telephone interview.