The Queen said the Royal Air force has 'defended our freedom gallantly' today as celebrations kicked off for the 100th birthday of the world's first air force.
On April 1, 1918, the Royal Flying Corps and the Royal Naval Air Service merged to create the RAF.
Centenary celebrations will last 100 days and feature a number of events, culminating in a service in Westminster Abbey on July 10, followed by a parade in The Mall and a flypast over Buckingham Palace.
Today began with a breakfast reception at a building on the Strand, London - the former site of Hotel Cecil which was the first headquarters of the RAF.
A printed message from the Queen was read out by Aircraftsman Adam Wood, from Aylesbury, who at just 16 is one of the youngest members of the RAF.
Celebrations have begun for the Royal Air Force as they mark the 100th birthday of the world's first air force. Pictured: Honorary Ambassador for the Air Cadets, Carol Vordeman MBE talking with guests
The Royal Air Force Pipe band (pictured) marked the arrival of the past veterans along with serving personnel and the current Chief of The Air Staff Sir Stephen Hillier with this performance
Veterans (pictured) and current service personnel held celebrations here today to kick off RAF100. The green plaque in this photo marks the site of the first HQ for the RAF
Left, Chief Of The Air Staff, Sir Stephen Hillier, signs the Royal Air Force Association Scroll while accompanied by Air Marshall Sir Baz North, President of the Royal Air Force Association. Right, Air Chief Marshal Sir Stephen Hillier and members of the RAF100 baton relay team
Aircraftsman Adam Wood, pictured, read out a letter from the Queen to a room full of dignitaries at the start of the series of events today. The 16-year-old, from Aylesbury, is the youngest Airman in the RAF
He told a room acked full of dignitaries including the Chief of the Air Staff Air Chief Marshal Sir Stephen Hillier and Chief of the Defence Staff Air Chief Marshal Sir Stuart Peach, that the Queen sent her 'heartfelt congratulations' as he read her message.
Also in attendance was Air Commodore Charles Clarke OBE, who was shot down over Germany and imprisoned in the camp from which 76 prisoners tunnelled out of during the 'Great Escape', and former Countdown presenter and honorary Group Captain, Carol Vorderman.
The Queen said in her message: 'The anniversary of the world's first independent Air Force is of great significance, and it is fitting to pay tribute to the tenacity, skill and sacrifice of the men and women who have served within its ranks over the last century, and who have defended our freedom gallantly.
'Through its enduring focus on professionalism, excellence and innovation, the Royal Air Force stands as a shining example of inspiration around the world today and for the next generation.
'May the glory and honour that all ranks have bestowed on the Royal Air Force light its pathway to the future guarding our skies and reaching for the stars.'
Air Commodore Charles Clarke OBE, who was shot down over Germany and imprisoned in the camp from which 76 prisoners tunnelled out of, is pictured talking with guests
Here, a veteran arrives at St Clements Danes Church, the RAF Church in Westminster, where a church service was held earlier today
The church, pictured, was heavily damaged in 1941 during the Blitz. Following an appeal for money by the RAF the