Britain confirmed the expulsion of an Israeli diplomat today after concluding Tel Aviv forged the UK passports used by the killers of a Hamas commander.
British Foreign Secretary David Miliband condemned Israel's "intolerable" actions in cloning the British documents carried by the hit squad that assassinated Mahmoud al-Mabhouh.
He said the misuse of the passports put British nationals in the Middle East at risk, and said the fact that Israel is a close ally added "insult to injury".
Twelve British passports were used by people involved in the killing of al-Mabhouh, the founder of Hamas's military wing, in his luxury hotel room in Dubai on January 19.
Dubai officials are "99% certain" that agents from the Israeli secret service Mossad were behind the murder, but Tel Aviv has refused to confirm or deny the link.
Mr Miliband told MPs an investigation by Britain's Serious Organised Crime Agency uncovered "compelling" evidence that Israel was responsible for cloning the British passports.
He said: "The government takes this matter extremely seriously. Such misuse of British passports is intolerable. It presents a hazard for the safety of British nationals in the region.
"It also represents a profound disregard for the sovereignty of the United Kingdom. The fact that this was done by a country which is a friend, with significant diplomatic, cultural, business and personal ties to the UK, only adds insult to injury.
"No country or government could stand by in such a situation."
He added: "I have asked that a member of the embassy of Israel be withdrawn, and this is taking place."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, said he was "disappointed" by Britain's response but stressed that the relationship between Israel and the UK is of "mutual importance".
He told reporters outside the Israeli Embassy: "It is our clear intention to strengthen the firm foundation of our relationship which is both vital and beneficial to both our countries."
This is the first time Britain has kicked out an Israeli diplomat since 1988, when an Israeli embassy attache was expelled amid claims he was involved in a Mossad operation to run a member of the Palestine Liberation Organisation as a double agent on British soil.
Mr Miliband stressed that Britain had no advance knowledge of the killing of al-Mabhouh and no involvement "whatsoever" in it.
The British Foreign Secretary said 11 of the 12 innocent British nationals affected have now been given biometric passports which would be harder to counterfeit.
He also said the British Foreign Office's travel advice for Israel would be amended to highlight the risk of papers being cloned, and how it can be minimised.
Other members of the alleged Mossad hit squad travelled on fake Irish, French and Australian travel documents.
British Prime Minister Gordon Brown supports the decision to ask the Israeli diplomat to leave Britain and is so far unaware of any plans by Tel Aviv to take tit-for-tat action to expel UK officials, his spokesman said.
Mr Miliband met Israeli foreign minister Avigdor Lieberman yesterday and handed him a letter seeking formal assurance that in future Israel will not be party to the misuse of British passports.
The British Foreign Office could not confirm the seniority of the Israeli diplomat who has been expelled.