Ehud Olmert, Israel's prime minister during the Gaza war, would probably face arrest on war crimes charges if he visited Britain, according to a UK lawyer who is working to expand the application of "universal jurisdiction" for offences involving serious human rights abuses committed anywhere in the world.

Neither Olmert nor Tzipi Livni, the foreign minister during the Cast Lead offensive, and a member of Israel's war cabinet, would enjoy immunity from prosecution for alleged breaches of the Geneva conventions, predicted Daniel Machover, who is involved in intensifying legal work after the controversial Goldstone report on the three-week conflict. Neither are ministers any longer.

Prosecutions of Israeli political and military figures remain likely despite the failure to obtain an arrest warrant for Ehud Barak, the defence minister, when he visited the UK earlier this month, he said. In the Barak case a magistrate accepted advice from the Foreign Office that the minister enjoyed state immunity and rejected an application made on behalf of several residents of the Gaza Strip.

"This needs to be tested at the right time and in the right place," Machover said. "One day one of these people will make a mistake and go to the wrong country and face a criminal process — and then it'll be a matter for the courts of that country to give them a fair trial: that's what the Palestinian victims want."

The death toll for the war was some 1,300 Palestinians and 13 Israelis. Israel insists it acted in legitimate self-defence in response to rocket attacks by Hamas.

Police sources denied a claim that police maintain a "watch list" of Israeli officers who would face arrest if they try to enter the country.

In 2005 General Doron Almog was tipped off that he was about to be arrested before leaving a plane at Heathrow airport. Last month a former chief of staff, General Moshe Ya'alon, cancelled a visit to Britain, apparently for fear of arrest. Ami Ayalon, former head of the Shin Bet security service, faced an arrest warrant in the Netherlands following a complaint by a Palestinian who said he had been tortured.

The development of universal jurisdiction has been boosted by the Goldstone report, which urged Israel to conduct an independent inquiry into alleged war crimes. Failing that, other governments were advised to try suspects using universal jurisdiction. Another option was for the UN security council to refer allegations to the international criminal court. Israel refused to co-operate with the report, which also accused Hamas of war crimes.

But the law is complex and developing unevenly. Lawyers in Germany were this week unable to obtain an arrest warrant for the current Israeli army chief of staff, Lieutenant General Gabi Ashkenazi, because German law grants immunity to guests invited on state visits. Spain is considered legally "dangerous" by the Israelis.

Machover confirmed that he was working with other lawyers in the EU and elsewhere "in an increasingly organised fashion in different jurisdictions. It's not just about Palestine. It might be about Rwanda or Afghanistan," he said.

Israel's Ha'aretz newspaper reported today that officers of the Israel Defence Forces who took part in the Gaza operation have been asked to consult legal experts at the foreign ministry, where they are instructed how to behave abroad and in some cases advised not to visit certain countries.

The ministry said it was "aware of efforts undertaken by Palestinian groups and their supporters to harm IDF officers through legal and public relations means, and is working to prevent such efforts."