"Your passport details could be captured for improper uses while your passport is out of your control. The risk applies in particular to passports without biometric security features," the Foreign Office's online advisory warns. "We recommend that you only hand your passport over to third parties including Israeli officials when absolutely necessary."
The warning informs British citizens of "a recent Serious Organized Crime Agency investigation into the misuse of UK passports" in connection with al-Mabhouh's assassination in January.
"The SOCA investigation found circumstantial evidence of Israeli involvement in the fraudulent use of British passports," the Foreign Office says.
Earlier Tuesday, British Foreign Secretary David Miliband told lawmakers that Israel was likely being the forged passports allegedly used in the Dubai assassination. He added that an Israeli diplomat was removed following an investigation into the use of 12 fake passports.
Miliband said Israel's actions had put British nationals at risk and showed "profound disregard" for Britain's sovereignty. Meanwhile, a British journalist urged Israel to fire Mossad Chief Meir Dagan over the passport affair.
Following Miliband's statement, Foreign Minister Lieberman said Israel attributes great significance to its ties with Britain.
"We maintain several dialogues with them on sensitive issues and regret the British decision," he said, adding that Israel had not bee presented with any proof pointing to its connection to the affair.