Abu Rumaysah al-Britani, born Siddhartha Dhar (24 June 1983) also known as Jihadi Sid,[5] is a British citizen who is an Islamic State (IS) militant.

On 3 January 2016, he was named as the lead executioner in a film issued by IS from Raqqa, Syria that showed the execution of suspected British spies against the Islamic State.

In a video he posted to YouTube, Dhar described IS's self declared caliphate as "...a dream for all Muslims worldwide ... We can finally have a sanctuary where we can practice our religion and live under the sharia.

[2] He spoke of his desire for the United Kingdom to be governed under sharia law on the BBC's Sunday Morning Live programme, and said of himself that he didn't "...really identify myself with British values.

Although he had been banned from travelling, Dhar departed for Paris from Victoria Coach Station in London with his wife, Aisha Tariq,[3] and their at the time four children, later arriving at Syria.