Part 5 Guards March Past the Queen in Slow and Quick Time

360 years of Trooping the Colour Queen Elizabeth II's Birthday Parade 2011
BBC

The Field Officer gives the command, "Officers, take post." Nos 1 to 5 Guard then "retire", aboutturning and rightforming into review formation. Nos 1 to 5 Guard then aboutturn again as the Corps of Drums play. (Since No. 6 Guard is already standing at right angles to the other five companies it does not need to execute this movement.)
Once intervals are established, the Field Officer salutes the Queen and informs her that the Foot Guards are ready to slowmarch, then commands, "Guards will march past in slow and quick time!" and orders the slow march.