Business travellers visiting Israel are being warned by the Foreign and Commonwealth Office (FCO) to protect their passports while passing through airports.
Updated travel advice on the FCO website urged Britons not to hand over their documentation to Israeli officials "unless absolutely necessary".
The stringent advice comes amid a growing diplomatic crisis between the UK and Israel after it was alleged the Israeli secret service, Mossad, used fake British passports to enter Dubai, where a high-profile Palestinian official was murdered.
The passports were believed to have been copied at Ben Gurion airport, South East of Tel Aviv.
The FCO advice stated: "UK passport holders should be aware of a recent Serious Organised Crime Agency (Soca) investigation into the misuse of UK passports in the murder of Mahmud al-Mabhuh in Dubai on 19 January 2010.
"The Soca investigation found circumstantial evidence of Israeli involvement in the fraudulent use of British passports. This has raised the possibility that your passport details could be captured for improper uses while your passport is out of your control."