Robin Millard   April 29, 2011 – 9:14AM GM

Prince William has made a surprise choice of a military uniform for his wedding on Friday, opting for the world-famous scarlet colours of the British army.

As a search and rescue helicopter pilot in the Royal Air Force, most had predicted William would wear his plain, blue RAF flight lieutenant’s uniform for his marriage to Kate Middleton at London’s Westminster Abbey.

However, the prince is also the honorary colonel of the Irish Guards infantry regiment and has chosen to wear their red tunic, his highest-ranking uniform.

His choice will likely be seen as a nod of recognition to those Irish Guards serving in Afghanistan.

The regiment deployed in October 2010 for a six-month tour of duty and has lost three soldiers on the current operation.

Their scarlet uniforms will be familiar to anyone who has seen the changing of the guard at Buckingham Palace.

However, the prince will not wear a bearskin hat — instead he will wear a peaked cap known as a forage cap. He will also be without a sword.

“It’s a personal preference what he chooses to wear but the main reason is it’s his senior honorary appointment in the army,” a spokesman for his St James’s Palace household told AFP.

“It is the highest-ranking uniform that he has at his disposal.”

Queen Elizabeth II made her grandson the colonel of the Irish Guards in February. It is William’s only honorary appointment in the army.

Though not as feverishly anticipated as Middleton’s dress, the prince’s uniform is nonetheless a surprise.

Some bookmakers had stopped taking bets on William wearing his RAF colours, with the odds reaching 20-1 on.

The last British royal wedding to feature a groom marrying in red was that of William’s aunt Princess Anne and Captain Mark Phillips at Westminster Abbey in 1973.

William’s Irish Guards uniform will be topped off with a gold and crimson sash and gold sword slings.

The insignia on the forage cap features the regiment’s Latin motto “Quis Separabit? (Who shall separate us?)”.

William will also wear his Garter sash and star, RAF “wings”, and the Golden Jubilee medal.

Based at the Victoria Barracks in Windsor, west of London, the Irish Guards recruit in Northern Ireland, as well as cities with large Irish populations such as Liverpool, London and Manchester.

Prince Harry, William’s younger brother and best man, is a newly promoted captain in the Household Cavalry’s Blues and Royals regiment and will wear the uniform of his new rank.

Their father Prince Charles will wear his Royal Navy admiral’s uniform, complete with a sword.