The service is something of a technical rehearsal ahead of the wedding of Prince William and Kate Middleton, which will take place at the venue just nine days from now.

During the service, the Queen handed out Maundy alms to 85 women and 85 men, marking each of her 85 years.

The two purses - one red and one white - are given to retired people as a mark of gratitude for their service to the church and the community.

The purses contain specially minted coins. This year, they include one coin commemorating the Duke of Edinburgh's 90th birthday in June and another marking the 2012 London Olympic Games.

Buckingham Palace said it was the first time that the Queen's birthday had fallen on Maundy Thursday.

The King's Troop Royal Horse Artillery provided a 41-gun salute at midday in Hyde Park, while the Honourable Artillery Company fired a 62-gun tribute from Gun Wharf at the Tower of London an hour later.