This year is an eventful one for the monarch as in the summer she will mark the 60th anniversary of her coronation, staged at Westminster Abbey on June 2 1953.
The monarch's milestone will be celebrated across the UK with traditional gun salutes fired in honour.
But as the birthday falls on a Sunday this year the military tributes will be held tomorrow.
Research has shown that since 1984 she has completed almost 15,000 official engagements.
The number, which includes visits to the United states, Australia, Jordan, Thailand and Oman, as well as her historic trip to Ireland in May 2011, will add weight to the argument that the Queen is one of the hardest-working heads of state in the world.
Although she has cut down on her official overseas trips, the Queen shows no signs of slowing down, carrying out 425 engagements in her Diamond Jubilee year last year, compared with 370 in 2011.
Already this year, she has notched up 19 events, in spite of having to spend a night in hospital with a bout of gastro-enteris in March.