Possible Clues:

• A standing item for many a public function
• Part of theatre greeting first lady of song
• "Pray we can hold on to the smaller one, which is more comfortable than the king"
• Prayer for a chess player?
• 'My Country, 'Tis of Thee' soundalike
• Many Brits stand for it
• E.g. Heaven's quoted, renewing call for ruler's divine protection
• '77 Sex Pistols classic
• Its tune is also used for 'My Country, 'Tis of Thee'
• A song that's guaranteed to get you on your feet