London, Sep 2 : A fourth man has been charged with possessing terrorist material following an investigation into an alleged threat to assassinate British Prime Minister Gordon Brown.
Muhammad Ali Mumtaz Ahmad, 24, from the Whalley area of Blackburn, is due to appear before Westminster Magistrates Court in London on Tuesday.
He is jointly charged with Abbas Iqbal, 23, and Ilyas Iqbal, 21, who were previously remanded in custody.
Police have been given more time to quiz a fifth man, arrested in Derby, the BBC reported.
Ahmad was arrested on August 26 as part of a counter-terrorism operation involving Lancashire and Greater Manchester Police.
He is charged with possessing an article for a purpose connected with the commission, preparation or instigation of an act of terrorism.
Police raided three properties during the operation in Blackburn and Accrington.
Brothers Abbas and Ilyas Iqbal were remanded in custody last Friday after being charged with possessing terrorist material.
Abbas Iqbal is also charged with disseminating terrorist publications, while Ilyas Iqbal is also charged with collecting or making a record of information likely to be useful to a person committing or preparing an act of terrorism.
A fourth man, Ishaq Kanmi, 22, is accused of soliciting murder and of belonging or professing to belong to al-Qaeda.
He also faces additional charges of inviting support for al-Qaeda and disseminating terrorist publications.