Tour companies are flying home all Britons left on the Indonesian holiday island of Bali.

Many returned in the immediate aftermath of last weekend's nightclub bombing, but others opted to stay on and complete their breaks.

Now, however, in the light of new Foreign Office advice, tour operators are making arrangements for the return of all UK tourists.

On Friday, it was confirmed that 11 Britons were killed in the blast while 21 officially remain missing.

UK Foreign Office Minister Lady Amos surveys the devastation

A memorial service will be held in St Paul's Cathedral, London, at 1700 BST next Friday to honour the victims, the Australian High Commission has announced.

It hoped the service would "provide comfort for people from all nations affected by this horrendous act".

In a further mark of respect, Union flags at Buckingham Palace and at British embassies and high commissions around the world will fly at half-mast on Sunday, which will be a national day of mourning in Australia.

News of the pull-out came as the UK Government insisted it had received "no specific warnings" of an imminent attack on Bali in answer to growing speculation that one had been given.

Warning row

Foreign Secretary Jack Straw said there was "generic threat information" which covered Bali and other Indonesian islands.

But he added: "We had no specific warnings of an attack in Bali. We didn't have any warnings. The US didn't, Australia didn't. It was for that reason we issued no warnings."

The government said a "generic" warning about Indonesia was posted on the Foreign Office website on 27 August, but this did not mention Bali by name.

That came after a warning from US intelligence in August about possible attacks in several "hotspots".

Thomas Cook is flying back all 250 of its clients still on the island and Kuoni will arrange for the remainder of its 400 customers to return.

All UK tour operators suspended all tours to Bali and Lombok earlier this week.

Earlier on Friday, Prime Minister Tony Blair told cabinet colleagues he was certain more attacks were being planned.

Helpline numbers

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The US State Department confirmed claims by Conservative leader Iain Duncan Smith that US citizens in certain countries, including Indonesia, were warned two days before the attack to stay away from nightclubs and other public places.

UK apology

On Friday, UK Foreign Office Minister Baroness Amos laid a wreath at the scene of last weekend's bombings - the popular Sari Club in the busy resort of Kuta Beach.

She apologised to bereaved relatives on behalf of the government for a lack of organisation over plans to bring home victims' bodies.

Lady Amos admitted that a "lack of co-ordination" had put the families under enormous pressure.

She said a proposal to establish a specialist disaster team to cope with such tragedies would be seriously considered by the Foreign Office.