Should The Queen be present, a preamble would begin 'May it please Your Majesty'.
If a member of the royal family is also the president or patron of the society that is holding the function, he or she is styled 'Your Royal Highness and President'.
It used to be the rule that no guest should leave a function before a member of the royal family, except in special circumstances when prior permission should be obtained.
However, when charity balls and dinners may continue well after midnight, it is probably practical for the organiser of the function to warn the private secretary that this rule may be honoured in the breach rather than in the observance.
To obtain the necessary silence, the Toastmaster may say, without preamble, 'Pray silence for your president/host/chairman etc'.
The first and principal Loyal Toast, as approved by The Queen, is 'The Queen'. It is incorrect to use such forms as 'I give you the Loyal Toast of Her Majesty The Queen'.
The second Loyal Toast, which, if given, immediately follows the first, is 'The Duke of Edinburgh, The Prince of Wales, and the other members of the royal family'.
The Loyal Toast in Lancashire, Greater Manchester and Merseyside, and at Lancastrian organisations elsewhere in the country, is 'The Queen, Duke of Lancaster'.
In Jersey the toast of 'The Queen, our Duke' (ie Duke of Normandy) is local and unofficial, and used only when Islanders are present. This toast is not used in the other Channel Islands.