From time to time, The Queen sends additional anniversary messages to mark special occasions.

For 1997 only, The Queen sent messages of congratulations to all those who were married in the same year as Her Majesty, to mark their golden wedding anniversaries. This was a special one-off gesture.

In 2007 over 18,000 couples celebrating their diamond wedding anniversaries received a specially-worded joint congratulatory message from The Queen and The Duke of Edinburgh.

Occasionally, messages have been sent to well-known or unusual recipients, perhaps the most famous of which was Queen Elizabeth The Queen Mother, who received an official 100th birthday greeting from her daughter in 2000.

The former ballerina Dame Ninette de Valois received a message wishing her 'a very happy day' in June 1998.

In May 2002, an event in Israel was held to celebrate Israel's 600 centenarians, inspired by the custom of The Queen's birthday messages. A message from The Queen was sent to the guests, saying:

'I am delighted to be able to send my very best wishes on the occasion of this morning's celebration to honour the centenarians of Israel.'