An alleged al Qaeda threat to the life of British Premier Gordon Brown is being investigated by authorities here on the eve of his tour to China and India.

The investigation follows claims that an Islamist website is setting up a branch of al Qaeda in Britain. The site, www.alekhlaas.net, speaks of the creation of the al Qaeda organisation in Britain. The site, put up on January 2, urges young Muslims to rise up against infidels such as 'Brown and (former prime minister Tony) Blair, BBC reported.

Although the threat was described as aspirational, Pauline Neville-Jones, former head of the British joint intelligence committee, said: "You don't ignore this sort of thing. It may not be a threat from an existing cell... But it does represent a move in the propaganda game and the propaganda game is not something we should ignore. This is after all a struggle over ideology," she told BBC.

The site reportedly hosts a catalogue of Islamist messages, musings and writings, and has been visited by more than 17 million people.

The threat was reported just days before Brown leaves on his trip to China and India -- his first to the two Asian giants as Britain's prime minister.

Talks about global security cooperation and the fight against terrorism figure prominently in his agenda in both countries.