On Thursday morning the Israeli ambassador in London will be summoned for talks with the British Foreign Ministry.
He will be questioned about the apparent use of forged British passports in the assassination of Hamas's Mahmoud al Mabhouh in Dubai. The incident is developing into a serious diplomatic incident between London and Tel Aviv.
Six of the eleven passports used by the alleged assassins in Dubai and displayed by the emirate's police on Monday were of British origin. All of them exactly match the names of real people currently living in Israel.
On Wednesday some of them spoke of their shock and dismay on hearing that their names had been associated with the assassination.
British born Stephen Hodes, 37, told Israeli television that he had not left Israel for two years,
"I don't know who is behind this. I am just scared, these are major forces," he said.
Another British citizen Paul John Keeley said he had been "walking around like a zombie."
"I woke up this morning and suddenly my life is like an espionage movie. It is all very worrying but I know I have not done anything wrong," he told Britian's Daily Mail.
There is widespread speculation that the Israeli secret service Mossad was behind the killing, although Israeli officials have refused to confirm it. On Wednesday Israeli foreign minister Avigdor Lieberman poured cold water on the speculation but did not issue a specific denial.
"There is no reason to think that it was the Israeli Mossad and not some other intelligence service or country up to some mischief," he told an Israeli radio channel.
But British officials are taking the matter very seriously. Prime Minister Gordon Brown got involved Wednesday telling a radio station in London the matter needed full investigation.
"The British passport is an important document that has got to be held with care," he said. Later the British Serious Organised Crime Agency was tasked with looking into the matter and will be liaising directly with authorities in Dubai.
A spokesman for the agency said "we can confirm that the photos and signatures on the UK passports used in Dubai do not match those issued by the UK government."
An unnamed British Foreign Office official was quoted by the BBC saying the government is "to take action that is necessary to protect British nationals from identity fraud."
Israel's Mossad agency has used foreign passports in its covert operations before and it has damaged relations with friendly countries. In 1997 it used two Canadian passports in the botched assassination attempt of Hamas leader Khaled Meshaal in the Jordanian capital of Amman. The incident upset both the Canadian and Jordanian governments.
During Monday's police press conference in Dubai investigators revealed the five other alleged assassins were travelling on Irish, French and German passports, all apparently forged.
Despite official silence at home, the Israeli press has given prominent coverage to the affair. Israel's ability to reach its enemies far from its own territory has long appealed to the public.
There has been a mix of admiration for the clinical professionalism shown in the Dubai operation, and concern that too many clues were left behind.
One of Israel's leading columnists wrote that the assassination "was an operational success but a strategic failure."
On Thursday morning Israel's ambassador in London may learn just how much diplomatic damage the alleged misuse of British passports may have caused.