The calls - from both Liberal Democrat and Labour MPs - follow the admission from Foreign Secretary Robin Cook that British-made jets were used by the Indonesians to intimidate the people of East Timor.

The Hawk jets, made by British Aerospace, were sold to the Indonesian Government with the clear understanding they would not be used in East Timor.

As a result the Labour chairman of the Foreign Affairs Select Committee, Donald Anderson, said the UK should sell no more military jets to Indonesia for the time being.

Liberal Democrat defence spokesman Menzies Campbell has criticised the government for maintaining Indonesia's invitation to the UK's largest arms fair, calling it "wholly inexplicable".

Menzies Campbell: The invitation is "wholly inexplicable"

He said there was a legal case to be made for the UK to revoke the rest of Indonesia's export licence for Hawk jets as it had admitted breaking the terms of sale.

"I have seen opinion from leading counsel which was obtained by some of the NGOs [non-governmental organisations] in London which argues very strongly that the licences could have been revoked," he said.

Menzies Campbell: The invitation is "wholly inexplicable"

Mr Campbell also called for the House of Commons to have the power to scrutinise arms exports. He said weapons exported from the UK had been used by the Indonesian Government not for internal security but so "they can prevent democracy operating in their own country".

Mr Anderson said the affair highlighted "the dangers of selling arms to dictatorial regimes like the previous regime in Indonesia".

But he said it was unclear if the Indonesians had broken the letter of the export licence terms.

He added that he thought arms sales should be suspended until it was certain that Indonesia would abide by the referendum result - which he expected would back independence.

'General security'

Indonesia's ambassador to the UK claimed that when the Hawk jets made two flights over the East Timor capital Dili on 16 July, they were merely providing general security.

The BBC Andrew Bomford: "One thing is not in dispute"

The row comes as votes are being collected from Monday's referendum on whether East Timor should become independent from Indonesia.

On Tuesday Defence Procurement Minister Baroness Symons confirmed the Indonesian visit to the UK largest arms fair would go ahead.

Baroness Symonds: "Indonesia has promised there will be no more flights"

She said the UK had received "absolutely specific assurances" from the Indonesian Government and military that there would be no repetition of the flights.

"Indonesia is a country in transition. It is an emerging democracy. And under the United Nations, like any other country, it has the right for self defence," Baroness Symons said.

Arms sales continue

Her comments are certain to enrage human rights groups who have long claimed that British-made defence hardware has been used for repression in East Timor since Indonesia invaded in 1975.

The UK has supplied more than 40 Hawks to Indonesia since the early 1980s.

Jakarta is still awaiting delivery of the majority of an order for 16 of the planes under a deal struck in 1996.

Baroness Symons defended the government's record on arms sales and added that the licence under which the Hawks were sold was granted by the previous Tory government.

"We don't sell arms that can be used for internal repression or external aggression and our code makes that very clear," she said.

Shadow Foreign Secretary John Maples has written to the Indonesian ambassador, Nana Sutresla, to express his party's "disappointment" at the breach of the export licence conditions.

Arms show

The Defence Systems and Equipment International exhibition opens at Chertsey, Surrey, and London's Docklands on September 14. More than 600 companies from 50 countries will be exhibiting.