By Defence Correspondent Jonathan Marcus

The Hawk, manufactured by BAE Systems, is one of the British aerospace industry's great success stories.

The prototype of this subsonic two-seat jet trainer first flew in 1974. Since then some 750 aircraft have been ordered or selected by 17 countries around the world.

The Hawk is used by the Royal Air Force to train fast jet pilots, and a version of the aircraft - the Goshawk - is similarly used by the United States Navy.

It has been sold in almost every part of the globe, with orders from Saudi Arabia and other Gulf states; from Finland and Switzerland; and from Kemya and Zimbabwe.

In the Far East the Hawk has been purchased by Malaysia and South Korea. And it has recently been selected as a training aircraft by both Australia and South Africa.

What makes the Hawk so attractive to some customers - especially in the developing world - is its versatility.

Although the basic version of the aircraft is unarmed it can be adapted to carry both a cannon and a variety of under-wing stores - like air-to-air missiles or bombs.

Thus it can be used in both air defence and ground attack roles.

It is this operational role that has caused controversy for successive British Governments both in Indonesia and now in Zimbabwe.

Such problems have been accentuated by the current UK Government's stated desire to introduce an ethical dimension into its foreign policy.

Nowhere are the conflicting demands of ethics and real politik more obvious than in the difficult area of arms sales.

External aggression

Political, diplomatic and economic factors must all be weighed up with sometimes conflicting advice from the arms manufacturers.

The Department of Trade and Industry, the Ministry of Defence; and the Foreign Office all have to be reconciled.

At one level all countries have the right to have weaponry to defend themselves from external aggression.

But often the same weaponry can be used for offensive purposes or to damp-down internal dissent.

It is an area where there are no easy answers. And all governments of the arms exporting nations know that such exports are vital for the well-being of their own defence industries and to secure jobs at home.