LONDON (AP) _ Riding in a horse-drawn coach past throngs of cheering fans, the Queen Mother Elizabeth disregarded bomb threats Wednesday and went to her 100th birthday party _ an outdoor pageant of singing, dancing, floats and even camels.

The hugely popular royal, mother of Queen Elizabeth II and widow of King George VI, will be 100 on Aug. 4. But celebrations began in earnest a week ago, when European royal families attended a St. Paul's Cathedral service of thanksgiving for her long and remarkably healthy life.

Early Wednesday, as the last arrangements for the afternoon pageant were falling into place, bomb threats at three underground railway stations shut down extensive central sections of the main transport system and forced most royalty fans to make their way on foot from mainline railway stations and parking lots.

One bomb was found, and the government said it might have been the work of a dissident Northern Ireland paramilitary group opposed to the 1998 peace accord.

But if the bomb planters were aiming to disrupt the Queen Mother's festivities, they didn't figure on the determination of the lady herself _ and the people who traveled into town to wish her a happy birthday.

``Nothing would stop us getting here,'' said 65-year-old Nina Haney, who traveled from St. Albans, 20 miles north of the capital. ``I think the Queen Mother is the greatest old lady in the land. She's done more for the royal family than all the others put together.''

``We are great fans of the Queen Mother because she was a figurehead during the war and she is a very remarkable lady,'' said Jill Charman, 62, who came from 50 miles away.

It was during World War II that the queen and her husband forged a permanent tie to the British public, and many of those who lived through the difficult years of loss, deprivation and bombing remain deeply loyal to the royal widow.

The royal family remained in London during German bombing that left parts of the city in ruins, especially the poor East End. When Buckingham Palace was hit, she said, ``I'm glad we have been bombed. It makes me feel I can look the East End in the face.''

The Queen Mother, with eldest grandson Prince Charles at her side, arrived at the parade ground in an open carriage pulled by two white horses and welcomed by waves of applause.

Dressed all in pink and wearing high heels, she made her own way up the stairs of the dais, relying only on her walking sticks, and insisted on standing to take the salute of hundreds of troops marching past.

The pageant, with a cast of 7,000 at the Horseguards Parade ground, was for ticket holders only. But those without tickets could watch on television or line up alongside the route to get a glimpse of the Queen Mother riding by.

Other members of the royal family also attended, but the monarch and her husband, Prince Philip, stayed away so no one would outrank the Queen Mother and she could, therefore, receive the salute of the troops.

The guest of honor waved back to the marchers and seemed to genuinely enjoy the parade when it took on a small-town quality, with agricultural exhibits and costumed children waving from floats.

A World War II Lancaster bomber and two Spitfire fighters flew over, along with the last airworthy Bristol Blenheim.

There were many memories of the war, from the music _ ``The White Cliffs of Dover'' and ``A Nightingale Sang in Berkeley Square'' _ to the elderly servicemen and women walking bareheaded past their former queen.

The Queen Mother waved and acknowledged greetings from all who passed by. But a special salute was reserved for the last surviving holders of Britain's highest medals for valor _ the Victoria Cross and the George Cross. For them, the entire audience and the royal family stood.

After a verse of ``Happy Birthday to You,'' the Queen Mother gave a rare speech _ in firm voice and without apparent reference to notes. It was a brief, ``heartfelt thank you'' to all the participants and onlookers.

``It's been a wonderful evening, and I'll just say God bless you all, and thank you,'' the Queen Mother said, before the audience sang ``God Bless the Queen.''

Looking more vital and alert after an hour and a half in the sun than she had at the outset, the Queen Mother climbed into a limousine with Prince Charles to make a slow lap around the parade ground _ a final bow to those whose loyalty brought them from around the country to wish her well.