The Queen will reflect on "a momentous and rollercoaster year" in her Christmas Day broadcast, Buckingham Palace has revealed.

The Palace has never previously publicised the theme of the monarch's annual message to Britain and the Commonwealth in advance.

But this year a brief preview is being trailed in television adverts.

The Queen is using a walking stick after straining a knee ligament at Newmarket last week, the Palace revealed on Monday.

She is said to be making a quick recovery from the injury, which is "not serious", and will be attending a church service on Christmas Day and continuing her family engagements.

It has been about as full a year as I can remember Excerpt from Queen's speech

In a preview of the broadcast on Monday evening, viewers saw a montage of extracts from the royal year with a voice-over by the Queen.

"As I look back over these past 12 months, I know that it has been about as full a year as I can remember," she said.

Preview footage included scenes from the Bali memorial service at St Paul's Cathedral, London, the 2002 naval review at Portsmouth and informal shots of the Queen travelling by train on the Gateshead Metro.

The Queen was seen in the White Drawing Room of Buckingham Palace, with photographs of the Queen Mother, King George VI and Princess Margaret beside her.

She was wearing a rock crystal and hand-painted brooch set with 100 diamonds, which she had given her late mother as a 100th birthday present.

'Her thoughts'

The speech has traditionally been filmed in great secrecy. On one occasion, when the content of the broadcast was inadvertently disclosed by a BBC court correspondent, the journalist left his post.

The Queen Mother died in 2002

BBC Royal correspondent Nicholas Witchell said the Palace was trying to reassert the broadcast's importance in the traditional British Christmas Day.

Former Royal press officer Dickie Arbiter said it was an "important message" to the nation.

He said: "They are her thoughts, in her words, without any outside interference.

"At the end of the day it is a programme, listed in the television magazines and newspaper - therefore why shouldn't it be trailed like other programmes?"

This year the Palace said the Queen would focus on the sadness and joy of 2002.

She would acknowledge the overwhelming public support she received during the Golden Jubilee, which marked 50 years on the throne.

Audience decline

The Queen would also reflect on the deaths of her sister, Princess Margaret, and her mother.

It is unlikely events surrounding the Old Bailey trial of former royal butler Paul Burrell will be mentioned.

QUEEN'S SPEECH VIEWING FIGURES

1987: 28m 2000: 9.8m 2001: 8.7m

Audiences for the Queen's speech have been declining in recent decades.

In 1987, the address attracted an audience of 28 million.

By 2000 it had slumped to 9.8m, and last year just 8.7m viewers tuned in.

The speech will be broadcast at 1500 GMT on both BBC One and ITV1.

But at the same time Channel 4 will show an "alternative Christmas message" from the wife of British rock star Ozzy Osbourne, Sharon.