<P> The St James' Palace detachment of the Queen's Guard, led usually by the Corps of Drums, and bearing the Colour (if the Queen is in residence, then this will be the Queen's Colour; if she is not, then it is the Regimental Colour), marches along the Mall to Buckingham Palace, where the Buckingham Palace detachment has formed up to await their arrival . These two detachments are the Old Guard . Meanwhile, the New Guard is forming up and are awaiting inspection by the Adjutant on the parade square at Wellington Barracks . The Band, having been inspected by the Adjutant, forms a circle to play music whilst the New Guard is inspected . The Guard provides a full Military Band consisting of no fewer than 35 musicians (usually, though not always, from one of the Guards regiments) accompanied by their Director of Music . When the New Guard is formed up, led by the Band, it marches across into the forecourt of Buckingham Palace . Once there, the New Guard advances towards the Old Guard in slow time and halts . The Old Guard presents arms, followed by the New Guard presenting arms . The Captains of the Guards march towards each other for the handing over of the Palace keys . The new reliefs are marched to the guardrooms of Buckingham Palace and St James' Palace where new sentries are posted . </P> <P> During this time the Band has taken its place by the centre gate, formed up in a half - circle, where it plays music to entertain the New and Old Guard as well as the watching crowds . During this period, the two regimental colours are paraded up and down by the Ensigns (usually junior officers of 2nd Lieutenant rank or equivalent). With the Old and New Guards formed up once again, the Old Guard and the Band march out through the centre gates in slow time to their Regimental Slow march played by the Band . At the end of the slow march, the Captain of the Old Guard gives the word of command to' Break into Quick Time' and with a brisk five pace roll from the drums, the Band leads the way back to Wellington Barracks . </P> <P> A detachment of the regiment on guard at Buckingham Palace and St James' Palace is also responsible for providing the guard at the Tower of London . As the Tower is still officially a royal residence and is also the location of the crown jewels, it remains the army's obligation to guard it . The Tower guard numbers one officer, 3 NCOs and 10 soldiers, and usually posts a sentry outside the Jewel House and one outside the Queen's House . As the protection of the Tower is their responsibility (in conjunction with the Yeoman Warders), the guard must also see it is secure at night (see Ceremony of the Keys). </P> <P> One of the public duties battalions or incremental companies is responsible for providing the guard at Windsor Castle . The location of the ceremony at Windsor varies; in the summer, when the Queen is in residence it usually takes place on the lawn in the Castle's quadrangle . In wet weather or winter to protect the lawn, or when the Queen is not in residence, the ceremony occurs outside the Guardroom by Henry VIII's Gateway at the foot of Castle Hill . </P>

Where does the change of guard takes place