Muttahida Qaumi Movements Rauf Siddiqui has written a letter to Britain Prime Minister David Cameron seeing ban on former Sindh minister Zulfiqar Mirzas activities in London. Earlier, fiery Mirza continued his war of the word with MQM, threatening that he would move to international court of justice if justice was not served. The confrontation between Mirza and MQM escalated as the dissident PPP leader reached London to hand over proofs to the Scotland Yard squad investigating murder of Dr Imran Farooq. In a statement issued here MQMs Sindh minister Rauf Siddiqui asked the UK PM to keep check on Mirzas 'suspicious activities in London. His statements are meant for triggering ethnic violence in Karachi, the letter stated, alleging that Mirza had been involved in various criminal activates in the city.