Avi Dichter was head of Shin Beth when Israel killed Saleh Shehada

The foreign ministry said an "extreme leftist" organisation was likely to file a legal complaint against Public Security Minister Avi Dichter.

He was the domestic intelligence agency chief in 2002 when Israel bombed a Hamas military leader's house killing him, his bodyguard and 15 civilians.

British law allows private citizens to file complaints of alleged war crimes.

"Minister Dichter has cancelled this trip following threats of him being arrested in Great Britain. This is an intolerable situation," said his spokesman Barak Sari.

He had been invited to London as keynote speaker at a counter terrorism seminar at Kings College.

The visit was called off after the UK government had been unable to guarantee him immunity, his office said, in the event of a private citizens complaint leading to an arrest warrant for war crimes.

'Mistaken attack'

The Shin Beth agency, headed by Mr Dichter between 2000 and 2005, helped plan the assassination of Hamas military commander Saleh Shehada in July 2002.

Nine children were killed in the raid. A one-tonne bomb was dropped on Mr Shehada's house. The dead included his wife and his three children.

In the face of international condemnation, including Israel's main ally the US, Israel conducted an investigation and concluded that the raid had been a "mistake".

In 2006, the Israeli army scrapped plans to send one of its generals to a course at a British military academy over fears he could be arrested on war crimes charges.

A year earlier, former Gen Doron Almog narrowly avoided arrest for his involvement in the Shehada assassination. He refused to leave his aircraft after a tip-off by Israeli diplomats.

Correspondents say this is the first time an Israeli minister has cancelled a visit over fears of a private citizen's complaint.