Arms pumping, she hurtled across the scrubby band of lichen and samphire that led down to the shingle. Now she was on the mudflats, too, the subterranean water seeping into each footprint left by her Doc Martens in the sand.

‘Stop that, you idiot!’

The puppy was worrying at an amorphous, soggy shape. He turned to look at her just as she grabbed at his collar. She yanked him away.

The floating object was a plastic bag: an old supermarket one, stretched and torn, its handles knotted, with two pale tentacles poking through. Grabbing a stick that floated nearby, she used the tip to lift it out of the puppy’s reach and looked nervously inside. Not a jellyfish, no: some other sea creature, pale and bloated, wrapped in seaweed. She intended to take the bag back with her for disposal later, but as she walked back towards the beach, the puppy straining against his collar at her feet, the contents slithered through a rip and plopped onto the damp, dark sand.

The girl assumed at first that it was a mutant, pale-coloured starfish, but on closer inspection, moving the seaweed aside with her stick, she realised it was something different. She marvelled for a moment at how almost-human it looked, with those tentacles like fingers at one end. Then she saw a glint of gold. Somehow one of the tentacles had got caught up in something metal, round and shiny. She peered closer and counted the baggy, waxy ‘tentacles’: one, two, three, four, five. The golden glint came from a ring on the little finger. The ‘tentacles’ had peeling human fingernails.

She dropped the broken bag and screamed fit to fill the sky.

The Queen felt absolutely dreadful in body and spirit. She regarded Sir Simon Holcroft’s retreating back with a mixture of regret and hopeless fury, then retrieved a fresh handkerchief from the open handbag beside her study desk to wipe her streaming nose.

If her headache hadn’t been pounding quite so forcefully, she would have found the right words to persuade her private secretary of the simple fact that one always took the train to Sandringham. The journey from London to King’s Lynn had been in the diary for months. The station master and his team would be expecting her in four and a half hours, and would have polished every bit of brass, swept every square inch of platform and no doubt had their uniforms dry-cleaned to look their best for the occasion. One didn’t throw all one’s plans in the air over a sniffle. If no bones were broken, if no close family had recently died, one soldiered on.

She picked up the telephone on her study desk and asked the switchboard to put her through to the duke.

He was awake, but groggy.

‘What? Speak up, woman! You sound as though you’re at the bottom of a lake.’

‘In the helicopter?’ he barked.

‘We can hardly use a 747.’ Her head hurt and she was feeling tetchy.

‘In the navy we were banned . . .’ wheeze ‘. . . from flying with a cold. Bloody dangerous.’

‘You won’t be piloting the flight.’

‘If it bursts my eardrums you can personally blame Simon from me. Bloody fool. Doesn’t know what he’s talking about.’

The Queen refrained from pointing out that Sir Simon was an ex-naval helicopter pilot and the GP who had advised him was thoroughly sound. He had his reasons for counselling in favour of a quick journey by air instead of a long one by rail. Philip was ninety-five – hard to believe, but true. He shouldn’t really be out of bed at all, with his raging temperature. Oh, what a year this had been, and what a fitting end to it. Despite her delightful birthday celebrations in the spring, she would be glad to see the back of 2016.

‘The decision is made, I’m afraid. We’ll fly tomorrow.’

She pretended she didn’t hear Philip’s wheezy in-breath before what would no doubt be a catalogue of complaints, and put the phone down. Christmas was fast approaching and she just wanted to be quietly tucked up in the familiar rural comfort of Sandringham, and to be able to focus on her paperwork without it swimming in front of her eyes.

The autumn and early winter had been fraught with uncertainty. The Brexit referendum and the US elections had revealed deep divisions in Whitehall and Washington that it would take a very steady hand to repair. Through it all, the Queen had played host to presidents and politicians, she had been a greeter of ambassadors, a pinner-on of medals and a host for charity events – mostly at Buckingham Palace, the place she thought of as the gilded office block on the roundabout. Now Norfolk drew her with its wide-open spaces and enfolding pines, its teeming marshes, vast English skies and freewheeling birds.

The following day the helicopter whisked the royal couple, blankets on their knees, dogs at their feet, past Cambridge, past the magnificent medieval towers of Ely Cathedral, the ‘ship of the fens’, and on, north-eastwards towards King’s Lynn.