British officials would not confirm that Carlos was wanted for the 1973 shooting of Joseph Edward Sieff, then president of Marks & Spencer and vice-president of the Zionist Federation in Britain. Scotland Yard would merely say it had 'not ruled out' questioning Carlos but declined to specify any offence. The Foreign Office said it was not aware of any warrant for his arrest. This was in contrast to a swift reaction in Germany, which said it would seek to extradite Carlos and try him for murder over a bomb attack in Berlin in 1983.
British pressure groups insisted Britain must use the detention of Carlos in France to seek justice over the attack on Sieff, who survived the bullet fired into his face at his home in St John's Wood, north London.
'I'd be very surprised, outraged even, if they don't seek to extradite or at least question him,' Helen Davis, director of the Britain Israel Public Affairs Centre, told the Independent.
Howard Schavarien, president of the Zionist Federation, said: 'I would certainly hope that any outstanding crimes committed by this man will now be investigated. It was an act of terrorism here; we are now undergoing a new spate of Islamic terrorism against Jewish and Israeli targets in this country. The Sieff shooting shows how long it has been going on. It would certainly send the right signal to show the files are still kept open.'
After the Sieff shooting, Carlos hid the gun at the West London flat of a Basque woman - one of several girlfriends here - where it was later found. Sieff survived thanks to a set of exceptionally strong teeth which deflected the bullet's impact, and to the presence of mind of his wife, who turned him over on his stomach to stop him choking. He was paralysed for a time, but recovered almost fully and lived for another nine years.
Sieff was at the top of a list of targets carefully prepared by Carlos a year before. His family had donated to Zionist causes; he had made frequent fund-raising trips to Israel; a month before the shooting, he had acted as host to Menachem Begin.
A month later, a bomb caused serious damage to the Israeli Bank Hapoalim in the City of London. No conclusive evidence exists, but eyewitness reports and records of Carlos's movements could indicate he was responsible for that too.