British Muslim fighter vows to hoist black flag of Islam over Downing Street and Buckingham Palace
A militant Islamist fighter [not Abu Osama] waves a flag and cheers as he takes part in a military parade along the streets of Syria's northern Raqqa provinceReuters

A British Muslim fighter who has reportedly been fighting on behalf of the Jihadi forces in Syria has pledged to hoist the "black flag of Islam" atop London's Buckingham Place and the Downing Street.

Claiming he is among the hundreds of estimated Britons who are fighting in Syria, Abu Osama, told Radio 5 Live that he has been aggressively involved in military training to wage a war against Britain, which he described as "pure evil".

Osama, speaking with a northern English accent, said: "If and when I come back to Britain it will be when this khilafah, the Islamic State, comes to conquer Britain, and I come to raise the black flag of Islam over Downing Street, over Buckingham Palace, over Tower Bridge and over Big Ben."

Hailing the 7/7 London bombers as "heroic lions", the suspect claimed he has been fighting in Syria for the al-Qaeda-linked al-Nusra Front. His claims, however, cannot be independently verified.

His belligent interview comes as scores of imams in the UK urge British Muslims not to go to Syria and Iraq, where there are raging battles of sectarian conflict.

In a open letter signed by more than 100 Islamic leaders, the imams say: "Ramadan, the month of mercy, teaches us the value of unity and perseverance and we urge the British Muslim communities to continue the generous and tireless efforts to support all of those affected by the crisis in Syria and unfolding events in Iraq, but to do so from the UK in a safe and responsible way."

Qari Mohammed Asim, the Leeds imam who was behind the letter, said: "The scale of the humanitarian disaster in Syria and the escalating violence in Iraq calls for an unprecedented response.

"As we near the end of the first week of Ramadan our message is simple - we have come together to urge British Muslim communities not to fall prey to any form of sectarian divisions or social discord."