The UK is to expel an Israeli diplomat over the use of 12 forged British passports linked to the murder of Hamas leader Mahmoud al-Mabhouh in Dubai.
Foreign Secretary David Miliband told the Commons there were "compelling reasons" to believe Israel was responsible for the passport "misuse".
He said: "The government takes this matter extremely seriously. Such misuse of British passports is intolerable."
Israel says there is no proof it was behind the killing in Dubai in January.
But Mr Milband said it was "highly likely" the Israeli secret service Mossad was involved and the fact that Israel was a close ally added "insult to injury".
BBC News - Britain expels Israeli diplomat over Dubai passport row