Security was tight as the Queen made a surprise visit to Hendon on Thursday to pay tribute to the work of the emergency services.

She visited the Metropolitan Police College in Aerodrome Road to open a memorial garden.

It honours the 876 London officers who have lost their lives during the force's 170-year history.

Passers-by, who had got wind of the visit because of the high security, gathered outside the training college to wave to the Queen as she sped away with a police motorcycle escort.

Maureen and Martin Dryer from the nearby Grahame Park Estate watched her arrive and leave with granddaughters Talia, three, and Yaell, two, from Liverpool.

Mrs Dryer, from Clayton Field, said: "I ran home to get my granddaughters when I heard the Queen was visiting. We are all very excited.

"She had a beautiful smile and waved at us, hopefully she saw the children. They are quite young but they were very excited at having come to London and seen the Queen."

Mrs Dyer added: "I'm a bit disappointed with the younger generation of Royals but I was born in 1942 and brought up with respect for the Royal Family."

Earlier with Metropolitan Police Commissioner Sir John Stevens, the Queen laid a wreath at the memorial in the heart of the garden.

She described the terrorist attacks in America as a stark reminder of the debt society owes to the police and other emergency services.

"The recent terrorist outrages in the United States have reminded us all in the starkest possible way of the debt we all owe, day in and day out, to the police and other emergency services," she said. "Those who make the ultimate sacrifice on our behalf in the line of duty and must never be forgotten." The Queen signed a book of remembrance in which the names of fallen officers are listed.

"The first entry dates from June 28, 1830 and the most recent is of March 13 this year," the Queen said. "Though separated by time, all are united by a common bond of duty and courage which led them to lay down their lives in the service of others."

About 150 relatives of deceased officers were present for the ceremony. They later met the Queen in private. She added: "We can only imagine the grief and loss that you, as families and friends of those we honour today, have had to bear.

"But I hope you will be able to draw comfort from the knowledge that the selfless commitment they showed endures in our memory and in the memory of all their colleagues who today share their pride in being part of the Metropolitan Police Service."

Sir John Stevens said: "As we gather today in this garden to dedicate this memorial stone we stand in honour of those who have shown more courage and paid a price more dear than any of us.

"We salute them. They are the bravest of the brave, men and women who have known the joys and pleasures of life and who have embraced mortal danger to protect us. Their last act in life was the discharge of their duty."

Among those at the ceremony were relatives of PC Yvonne Fletcher, shot dead outside the Libyan Embassy in April 1984, and relatives of PC Keith Blakelock, hacked to death during the Broadwater Farm riots in Tottenham in 1985.

October 25, 2001 18:17

MATTHEW NIXSON