Watch The Queen's Guards: A Year in Service

It's finally the big day in Windsor and all eyes are on the Coldstream Guards as they lead the procession for the Queen's Birthday Parade. It will be Lt Col David Marsham's first time in charge of this iconic parade, the most high-profile ceremonial event of the year. It's also Lt Hugh Scrope's and new Guardsman Lubin's first time to feel the pressure of this global event.

Rehearsals for the Queen's Birthday Parade are ramping up and with the more than 300 guardsmen and horses involved, Garrison Sergeant Major Vern Stokes has to make sure everyone is up to scratch. For Lt Col David Marsham, this is his time time he has commanded such a parade and a lot rests upon his shoulders.

25 Platoon?have finished training and pass out from Catterick ready to start their new lives in central London, living only metres?away from Buckingham Palace. They move into Wellington Barracks, get fitted with their great coats and even learn how to wash their coveted bearskins.

News breaks of the death of HRH The Prince Philip, Duke of Edinburgh, and instantly the Coldstream Guards are drafted in to begin preparations for their most important ceremonial occasion in decades. With 30 years of experience, Garrison Sergeant Major Vern Stokes is in charge of the event and heads up mass rehearsals in Pirbright, where he has to get some rusty soldiers up to scratch.

The Coldstream Guards in Windsor at Battalion HQ are preparing for the most important inspection of the year.? They will find out if they're ready to take on this season's biggest Royal and ceremonial duties, known as going on 'The Blue Line'.