As the diplomatic row escalated, David Miliband condemned the counterfeiting as 'intolerable' and demanded Israel give assurances that UK citizens would never again be drawn into such an operation. Describing the passport holders as "wholly innocent victims," the Foreign Secretary said that the fact that Israel was a friend of the United Kingdom added "insult to injury". Expelling a diplomat is considered one of the most serious diplomatic sanctions can be taken against another country. Mr Miliband said: "The request for an individual to leave, and the decision of the Israelis to accede to that, was made by us. It was linked ... to the investigations that have taken place. "We've been very clear with the Israelis about the basis which we were asking the individual to leave." An investigation by the Serious and Organised Crime Squad (Soca) concluded that there were "compelling reasons" to believe Israel was responsible for the "misuse" of a dozen British passports. The probe determined that the documents were cloned when British citizens passed through airports on their way into Israel, with officials taking them away for "checks" which lasted around 20 minutes. A senior diplomat at the Israeli Embassy in London thought to be the Mossad's station commander in teh UK was expelled as a result. The Foreign Secretary told MPs that Britain had no advance knowledge of the "very sophisticated" operation to clone passports while their holders were travelling through Israel and other countries. He added: "Given that this was a very sophisticated operation, in which high-quality forgeries were made, the Government judges it is highly likely that the forgeries were made by a state intelligence service. "Taking this together with other inquiries, and the link with Israel established by Soca, we have concluded that there are compelling reasons to believe that Israel was responsible for the misuse of the British passports. "The Government takes this matter extremely seriously. Such misuse of British passports is intolerable." He added: "I have asked that a member of the embassy of Israel be withdrawn, and this is taking place." Israel's ambassador to London, Ron Prosor, who was summoned in to the Foreign Office be told the news, said he was "disappointed". A spokesman for the Israeli foreign ministry said: "The relationship between Israel and Britain is mutually important. We therefore regret the British decision." Israel has insisted there was no proof to show it was behind the killing in January but officials said there would be no tit-for-tat diplomatic expulsion. However, members of the Israeli parliament likened the British government to "anti-Semitic dogs" and demanded the expulsion of Britain's military attach in Tel Aviv in response. "I think the British are being hypocritical, and I do not wish to insult dogs here, since some dogs show true loyalty, [but] who gave the British the right to judge us on the war on terror?" said Arieh Eldad, a right-wing member of the Knesset. Another MP, Michael Ben-Ari, said: "Dogs are usually loyal, the British may be dogs, but they are not loyal to us. They seem to be loyal to the anti-Semitic establishment. "We have learned that a dog must be called by its name. This is anti-Semitism disguised as anti-Zionism." A spokesman for Hamas said it welcomed the decision to expel the diplomat but called for increased international efforts to track down the killers.