The Queen is expected to address the nation today with a eulogy for her mother.

The address is also expected to thank the people who have queued around the clock to pay their respects at the Queen Mother's coffin as it lies in state, in Westminster Hall.

On the eve of her mother's funeral service, the Queen will speak to the nation from Windsor Castle. She is expected to give thanks for the Queen Mother's long and eventful life.

The Queen is likely to set the tone for tomorrow's funeral service in Westminster Abbey which, although a solemn occasion full of pageantry, is an opportunity to celebrate the Queen Mother's 101 years.

Also today, the Queen Mother's four grandsons - Charles, Andrew, Edward and David Linley - will stage a vigil at her coffin.

They will echo history in a ceremony reminiscent of a royal vigil, on the same spot at Westminster Hall, for King George V, in 1936.

They are expected to perform a 30-minute Vigil of the Watch, late in the afternoon, as people continue to file past the coffin, paying their respects.

More than 500,000 people will have paid tribute to the Queen Mother by the time she is laid to rest tomorrow evening at Windsor, alongside her late husband, King George VI, and the ashes of her daughter, Princess Margaret.

About 400,000 people lined the route of her funeral procession through the capital on Friday and, since then, people have queued almost non-stop to pay their respects in Westminster Hall.

Large crowds are expected to turn out tomorrow morning for the funeral procession from Westminster Hall to Westminster Abbey.

The service will be relayed on loudspeakers along The Mall and outside Westminster Abbey, on North Green.

The queue to see the Queen Mother lying in state reached its longest so far yesterday, stretching three miles. Some 3,000 people were filing past the coffin each hour.

The Duke of York, with his daughters, Princess Beatrice, 13, and Princess Eugenie, 12, visited people queuing and said he was overwhelmed by the number of people paying their respects to his grandmother.

Meanwhile, preparations were under way at the abbey for the funeral service.

A mass of the Queen Mother's favourite English summer garden flowers will adorn the abbey. Arrangers were working on displays of more than 2,000 blooms.

The flowers, including fragrant lilies, will be set in informal, rather than stylised, arrangements.

The choristers of Westminster were in rehearsals for the service.

Choirmaster and organist James O'Donnell said the boys, aged from nine to 13, were approaching their final rehearsals in a professional manner, despite knowing that the gaze of millions of TV viewers would be on them.

The 22 boys, with others from the choir of the Chapels Royal, as well as adult choristers, will have the difficult task of singing as they walk down the aisle of the abbey, ahead of the cortege.

Hymns will include Immortal, Invisible, God Only Wise, and Guide Me Oh Thou Great Redeemer, with psalms and anthems.

Mr O'Donnell, 40, who was master of music at Westminster Cathedral before moving to the abbey in January 2000, wrote the music for the psalm which was sung as the Queen Mother was taken into Westminster Hall to lie in state, on Friday.