The front row is empty still.

‘Is he here?’ Margaret whispers, crowding at her shoulder.

‘Not yet.’ Elizabeth steps back from the curtains, disappointment a leaden weight in her stomach which is already rolling queasily with anticipation and stage fright. This will be the fifth performance of Aladdin, and though she knows all her lines, still there is that moment when the curtains are hauled back and the terror of failure clutches at her throat.

‘Let me see.’ Margaret elbows her sister aside and takes her place at the curtain as if she can conjure Prince Philip of Greece into space by the sheer force of her will.

Sometimes Margaret’s will is so strong, Elizabeth almost believes she could succeed but on this occasion her sister’s drooping shoulders indicate failure. She lets the curtains drop back into place and turns back to the stage, kicking at her satin skirts.

‘Papa said Philip would come,’ she pouts.

‘For Christmas,’ Elizabeth reminds her, trying to disguise the dullness in her voice. ‘He didn’t promise to come for the pantomime. Something may have come up.’

Margaret stares. ‘Something more important than joining the King and Queen to watch their two daughters perform?’

‘Philip’s a prince. He’s not going to be impressed by a couple of princesses.’ It is Elizabeth’s secret worry. She has spent her whole life being special, and now, the one time it matters, she may not be – at least, not for Philip.

It’s been two years since Philip of Greece took tea with the King and Queen. Elizabeth and Margaret sat enthralled as he entertained them with his wartime experiences at sea, deliberately making light of his own part and playing up the funny side of things. For Elizabeth, whose only memory of Philip up to that point had been of a bumptious cadet who had showed off terribly, it had been a revelation. The swaggering boy had been replaced by a young man who was everything a prince should be: brave, witty, charming.

And handsome. The memory of those penetrating blue eyes has been a tiny, insistent throb inside her ever since.

Not long afterwards, the royal family were invited to a party at Coppins, where Philip was staying with his cousin, Marina, Duchess of Kent. Philip asked Elizabeth to dance, either out of kindness or out of duty. She knew that much. She was fifteen and tongue-tied, burningly aware of his hand at her waist, his palm pressed against hers.

She is seventeen now. She longs for him to see that she has grown up.

‘He ought to want to come and see us,’ says Margaret stubbornly. She’s been looking forward to impressing him with her acting skills. ‘Especially you,’ she adds, uncharacteristically ceding centre stage to Elizabeth. ‘He’s been writing to you.’

‘Sometimes.’ Ever cautious, Elizabeth won’t even admit to her sister how she has pounced on Philip’s rare letters, how many times she has read and reread them, smoothing out the creases in the paper. They have told her nothing because what could they say? That he has remembered her, that’s all. But it has been enough. ‘He probably writes to lots of people.’