THE Queen paid tribute today to the professionalism, skill, determination and courage of the RAF, as she presented the service with new Colours in celebration of its 90th anniversary.

She told 5,000 guests at RAF Fairford in that she was "deeply conscious'' of the difficulties posed by campaigns in Iraq and Afghanistan.

She was speaking after presenting new Queen's Colours jointly to the RAF in the United Kingdom and the Royal Air Force Regiment, at the opening of the Royal International Air Tattoo.

The Queen and the Duke of Edinburgh were met by Air Chief Marshall Sir Glen Torpy, and watched a parade of 759 RAF personnel in the morning sunshine.

Wearing a lilac dress with pink trim, and a pink hat, she told the assembled ranks on the parade ground: "This is the fifth time I have presented the Royal Air Force with a new Colour.

"On each occasion I have been enormously impressed by the professionalism, skill, determination and courage with which the men and women of the RAF serve, often in the most challenging and dangerous of circumstances.

"Current operations in Iraq and Afghanistan have thrown a spotlight on the many achievements of the Service, of which you can all be immensely proud.

"However I am also deeply conscious that this success sometimes comes at a great cost to the Service, individuals and their families.

"I hand over my Colour with the confidence that you will guard it well, just as you continue to guard your heritage, ethos and unique contribution to defence.'' The Air Tattoo, the world's largest military air show, will open to the public tomorrow.

This afternoon the royal couple were meeting RAF personnel from every decade of the 90 years of the Royal Air Force - including Henry Allingham, 112, the oldest surviving veteran of the First World War.

They will later view an RAF Mass Flypast to mark the 90-year milestone.

The demonstration will involve 90 aircraft and will be the largest since the flypast to mark the 50th anniversary of the Battle of Britain in 1990, when 168 aircraft flew over Buckingham Palace.

Queen's Colours are awarded by the Sovereign in recognition of service achievement.