The heightened threat of suicide bombings was last night forcing UK embassies around the world to re-evaluate their defences against what an al-Qaida statement described as its "cars of death". The explicit warning of fresh "martyrdom operations" was published as police in Istanbul detained seven suspects in connection with the devastating blasts at the British consulate and the HSBC bank. All are understood to be Turkish passport holders. Two of them, tentatively identified by the Turkish media as Azad Ekinci and Feridun Ugurlu, were close friends of Mesut Cabuk and Gokhan Elaltuntas, the men who carried out the suicide bombings...