Baroness Thatcher remained silent throughout the ceremony

Lady Thatcher stood in silence during the London ceremony to remember the 255 Britons who died during the 74-day war.

She laid a wreath bearing the message: "In memory of those who have given their lives for Britain and for the Falkland Islands."

Earlier, Prime Minister Tony Blair met Falklands veterans in Fife.

The war also claimed the lives of 655 Argentines and three islanders.

Wreath laid

Lady Thatcher was prime minister when Argentina invaded the islands on 2 April 1982 and dismissed advice from defence officials who feared the islands, 8,000 miles from Britain, could not be re-taken.

At the service on Monday, she wore a long black coat and black shoes and laid a wreath of yellow and white roses, lilies and orchids at the foot of the Falklands memorial at the cathedral.

They were fighting in some of the most difficult circumstances. It took a lot of courage and a lot of commitment Tony Blair BBC scooped invasion news Argentina marks invasion Business as usual

She was accompanied by Sukie Cameron, the Falkland Islands representative in Britain, who also laid flowers at the memorial.

Lady Thatcher stood with her head bowed as Canon Lucy Winkett offered prayers, and did not speak for the duration of the ceremony.

Earlier, Mr Blair met Falklands War veterans on board HMS Liverpool at the Rosyth dockyard, in Fife, and said he was honoured to do so.

"I think we should sometimes just remember that we lost in the Falklands some 250 or more of the armed forces," he said.

'Tremendous sacrifice'

"And when we put that in context and we think of the losses in Afghanistan and Iraq which are actually less than that - we know just what a tremendous sacrifice and commitment those people made.

"And it was a very very tough endeavour for everybody. They were fighting in some of the most difficult circumstances. It took a lot of courage and a lot of commitment."

Mr Blair presented the ex-servicemen - from the Scots Guards and Royal Navy - with veterans' badges and certificates

Mr Blair met veterans on board HMS Liverpool

HMS Liverpool, a Type 42 destroyer, has just undergone a three-month refit and is set to return to active duty.

Among those meeting Mr Blair were Lt Cdr Nigel Smith, who was a 19-year-old able seaman on board HMS Active in 1982.

Others included retired Navy officer Bill Gossam MBE, Scots Guard Paul McLaughlan, from East Lothian, and Ian Kaye, from Aberdeen, who took part in the battle of Mount Tumbledown.

Mr Blair was taken on a tour of the ship, watching a simulated air defence exercise and a demonstration of fire fighting techniques - many adapted from lessons learned during the Falklands War.

He recently saluted Baroness Thatcher's courage in deciding to fight to reclaim the Falklands.

His visit on Monday coincided with the announcement of a �6m contract, which will see another Type 42 Destroyer - HMS Gloucester - undergo improvements and repairs at the same yard.