LONDON (AFP) - An al-Qaeda plot to blow up the British embassy in Yemen was foiled in September, the BBC reported Friday, quoting London's ambassador to the country as saying that the threat was "very serious".

The Foreign Office in London did not confirm the BBC story.

BBC television said 20 militants had confessed to planning to crash a truck bomb through the embassy gates after they were caught by Yemeni intelligence. Asked how serious the threat was to blow up the British embassy, Francis Guy, London's ambassador to Yemen said: "I think it was very serious."

She also suggested that there had been other similar earlier plots.

"We are very conscious that we are a high priority target here in Yemen and we try out best on a daily basis to review our security and improve it as much as we can," Guy told the BBC. A spokesman for the Foreign Office in London told AFP: "I'm not going to comment on security of individual embassies and high commissions. Security of staff is of paramount concern. There is no one-size-fits-all approach to security."