LONDON - After much pressure and many promises, Britain finally took steps yesterday to change its controversial law on universal jurisdiction to make it harder for foreign politicians and army officers to be arrested for war crimes while visiting.

The proposed legislation, which was tucked inside Wednesday's Home Office Police Bill, would require any future arrest warrant for crimes against humanity to be signed by the director of public prosecutions, who is appointed and supervised by a government minister, the attorney general.

Currently, such a warrant can be obtained just by presenting evidence to the City of Westminster Magistrates Court.

In practice, this change would make it much harder - though not impossible - for courts to issue such arrest warrants. The new system would also delay proceedings, so any suspect would have ample time to evade arrest by leaving the country.

Amnesty International and the Palestine Solidarity Campaign immediately put out a statement voicing opposition to the proposed changes. "Our justice system should not be altered according to the wishes of senior politicians from Israel - who are fearful of arrest because of decisions they have personally taken," said Sarah Colborne, the Palestine Solidarity Campaign's director.

Several Israeli leaders, including Defense Minister Ehud Barak, head of the opposition Tzipi Livni and, most recently, Deputy Prime Minister Dan Meridor have either canceled or cut short visits to London in recent years for fear of being arrested under the law.

The situation led Israel to announce during British Foreign Secretary William Hague's visit to the Middle East last month that it was postponing a strategic dialogue on security until Britain could guarantee that the law would be changed.

The changes still need to be approved by parliament to take effect, a process that could take months. Around 110 mainly Labour and Liberal Democrat members of parliament have indicated they oppose them, but they constitute only a small minority of the house.

Moreover, Shadow Home Secretary Ed Balls made it clear last month that Labour backed the proposed reform. Gordon Brown, the former Labour prime minister, had long spoken of pushing such changes through himself, but was reportedly thwarted by resistance from then-Justice Secretary Jack Straw and early elections. The matter was thus left for Prime Minister David Cameron's coalition government to deal with.