Nicholas Witchell BBC royal correspondent

It was extremely solemn. This was a service attended by 450 members of family and close friends.

A congregation in its middle-age. People who had clearly known Princess Margaret for a number of years.

With the men in morning suits, the women in black it was of course a very sombre atmosphere within St George's Chapel.

The princess's coffin resting in the choir area close to the high altar, covered with her personal standard and flowers and a wreath of pink tulips and white roses from the Queen Mother.

A crowd of several thousand gathered outside the Castle

The Queen Mother was indeed there, as all her friends expected her to be, looking fit but frail.

She was driven to St George's Chapel in a vehicle specially adapted for someone in a wheelchair and as we understand it, she was taken into the chapel in that wheelchair to her position, close to where her younger daughter's coffin rested.

Other members of the Royal Family led by the Queen, with the Duke of Edinburgh, the Prince of Wales, Princes William and Harry entered the chapel with Princess Margaret's immediate family - her son and daughter, Viscount Linley and Lady Sarah Chatto and her former husband the earl of Snowdon.

And, also in the congregation, other close friends including Roddy Llewellyn, the man with whom Princess Margaret had a seven-year affair in the 1980s.

Arts enthusiast

However, Princesses Beatrice and Eugene, the Duke of York's two daughters, were not at the service, we understand, and nor was Princesses Alice of Gloucester - who is 100 years old.

But otherwise this was a very extensive representation of the British Royal family.

Princess Margaret was enthusiastic about the arts and had many friends in the fields of art, culture and ballet and the congregation reflected those close connections.

The princess had specified the music and the readings that she wanted.

Favourite hymns

These reflected her intense Christian faith and her interest in culture.

For example, music from Swan Lake was included in the selection played prior to the service and during it the congregation heard Psalm 23, and a reading from Romans Chapter 8 by Viscount Linley.

Also in the order of service were favourite hymns: Immortal Invisible; God only Wise; When I Survey the Wondrous Cross.

And the service ended with the sounding of the last post and then a lament - which was played by a piper and entitled the Desperate Struggle of the Bird.

Perhaps a metaphor for the, at times, troubled life that this princess led.