Islamic extremists determined to attack Britain with chemical or radiological weapons have made attempts to acquire such dangerous materials, a senior British diplomat said Monday. Britain's Foreign Office has evidence of efforts by terror groups, including al-Qaida, to purchase chemical, biological, radiological and nuclear materials for use in attacks, the official said on condition of anonymity because of the sensitive nature of his work. The senior diplomat said there was no doubt al-Qaida terrorists hoped to use chemical and radioactive material against Britain and other Western targets. "We know the aspiration is there, we know the efforts to get the materials are there, we know the efforts to get the technology are there," he said. The diplomat acknowledged that an attack with chemical or radiological weapons would most likely be mounted with crude technology and cause mass panic rather than mass casualties.