THE former head of Mossad, the Israeli Secret Intelligence Service, says we are in the throes of a new world war where the objective of the terrorist is not regime change or territorial gains but despatching western civilisation into history.

Efraim Halevy, who recently stepped down as the head of the Israel National Security Council and national security adviser to the Israeli prime minister, said we were in for the long haul and must brace ourselves for more that will follow.

Halevy, who was also an Israeli ambassador to the European Union, warned: "Thursday's attacks on the London transport system were the work of perpetrators who had an operational capacity of considerable scope. They have come a long way since the two attacks of 1998 against the American embassies in Nairobi and Dar es Salaam, and the horrors of September 11, 2001.

"There was careful planning, intelligence-gathering, and a sophisticated choice of timing as well as near-perfect execution. We are faced with a deadly and determined adversary who will stop at nothing and will persevere as long as he exists as a fighting terrorist force.

"We are in the throes of a world war, raging over the entire globe, and characterised by the absence of lines of conflict and an easily identifiable enemy. There are sometimes long pauses between one attack and the next, consequently creating the wrong impression that the battle is all over."

Halevy who is now a special adviser to Quest, a London-based security and intelligence consultancy, is seen as one of the world's most eminent authorities on terrorism, with extensive security service contacts.

He said the 'great wars' of the 20th century lasted less than this war, and the end was nowhere in sight. "The aim of the enemy is not to defeat western civilisation but to destroy its sources of power and existence, and to render it a relic of the past.

"It does not seek a territorial victory or a regime change; it wants to turn western civilisation into history and will stop at nothing less than that.

"It will show no mercy or compassion and no appreciation for these noble values when practised by us. Unfortunately, it cannot be said that seven years after this war broke out at the embassies in east Africa, we can see its conclusion.

"For a while - too short a while - we are engrossed with the sheer horror of what we have seen and heard, but with the passage of time our memories fade and we return to our daily lives, forgetting that the war is still raging out there and that more strikes are sure to follow.

"In practice, no government today can provide an effective 'suit of protection' for the ordinary citizen. There can be no protection for every bus, every train, every street, every square. In these times the ordinary citizen must be vigilant and must make his personal contribution to the war effort.

"This war is already one of the longest in modern times. As things appear now, it is destined to be part of our daily lives for many years to come - until the enemy is eliminated - as it surely will be."