‘It was the bleedin’ excitement on their faces fixed me,’ he told his wife that evening.

Five minutes later, Meredith and Tristan, having enjoyed a merry champagne brunch at the Heavenly Host, bounced into Bussage’s parlour to find Rannaldini, immaculate in a pinstripe suit and shocking pink tie, autographing a pile of photographs.

‘Helen said you were here,’ giggled Meredith. ‘The helicopter’s waiting. What the hell did you do to that sweet Fancy Fish man? He’s just taken the side off Tristan’s flash car.’

Booked in for a two-hour trip round the state rooms, which was all the time Rannaldini could spare, they lunched beforehand at Green’s in Bury Street. Over oysters, lobster and Sancerre, they decided they needed ideas for the Great Hall, which was going to be turned into Philip II’s bedroom. They also required a set, probably the Summer Drawing Room, into which Philip summoned Carlos from the polo field for a pep talk. This was a duet composed by Rannaldini, so he didn’t want a too-spectacular décor to distract people from his music. But they could go to town on the state room in which Philip had his great political debate with Posa, which had only been written by Verdi. For this Rannaldini had evil designs on Helen’s Blue Living Room.

Arriving at the Palace, Meredith commandeered the red guidebook. ‘That’s the arch through which diplomats and heads of state enter,’ he announced, as they peered down into the pink-gravelled quadrangle.

‘Her Majesty lives on the opposite side,’ said Rannaldini, pointing to a dark blue door.

‘Why don’t you give her a bell?’ suggested Meredith. ‘Ask if we can pop in for a brandy. You must have met her when she gave you your K.’

‘And on many other occasions,’ said Rannaldini icily. ‘Anyway,’ he added, looking up at the empty flagpole, ‘she is not in residence.’

‘“In 1826 George IV chose John Nash to design a new palace,”’ read out Meredith, ‘“but he was hampered by a chronic lack of funds.” Nash et moi. I expect he gnashed his teeth.’ Rather like a child swinging between two parents, Meredith linked arms with Tristan and Rannaldini. ‘You will give me a decent budget, won’t you, boys? We can’t stint on royalty. Oh, look, they’ve got Sky Television. Lovely to think of that butch Prince Andrew watching all that golf.’

Tristan was gazing up at the lion-coloured columns of the ambassadors’ entrance.

‘The English stole the idea for that double portico from the Louvre,’ he grumbled. ‘They steal all our decent ideas.’

‘Well, we won both of those,’ Meredith waved the guidebook at two panels celebrating the battles of Trafalgar and Waterloo, ‘so boo sucks.’

‘Weeth a little help from the Germans,’ said Rannaldini crushingly. ‘Now concentrate. Not now,’ he snarled, as a group of middle-aged tourists tiptoed up reverently in the hope of an autograph.

Meredith was disappointed the tour didn’t include the ballroom. ‘You’re only admitted’, announced Rannaldini pompously, ‘if you’re getting a decoration.’

‘Get you,’ said Meredith, who was now busily sketching a grand staircase, which unfurled like the frill round a golden wedding cake.

Tristan, lost in thought, was admiring a lovely marble of a lurcher having a thorn removed from its paw by Diana the huntress. He must find a postcard to send to Lucy Latimer. Thank God he’d booked her to do the make-up and to calm Hermione and Chloe when filming started. There were dogs in every painting too, which meant he’d have to include lots in the film. Dogs, he reflected wearily, were almost more of a nuisance than children.

‘This is the Green Room,’ Rannaldini paused on the threshold, ‘where one mingles before proceeding to the Throne Room to meet one’s hosts.’

‘How lucky we are to have you to initiate us,’ said Meredith gravely.

‘Stop taking the pees, you little popinjay,’ said Rannaldini. ‘How about this décor for one of the drawing rooms?’

‘No good for your colouring,’ said Meredith firmly. ‘Green’s awful with grey hair and a sallow complexion. Someone would spear you with a cocktail stick. Although we could drag the dungeons this colour to cast a sickly glow on poor, doomed Posa.’

Tristan kept having to hide his laughter by examining paintings.

‘This is how I want room where Posa defies Philip,’ said Rannaldini, as he hustled them into the Throne Room, which was the length of a cricket pitch. The crimson silk walls were lined with gold sofas. Huge cut-glass chandeliers glittered from the ceiling like a fleet of Jack Frost’s air balloons.

‘The ceilings at Valhalla are too low for chandeliers,’ protested Meredith.

‘Then raise them,’ said Rannaldini imperiously.

Through an arch flanked by white-winged genii holding gold paper chains, burgundy red steps led up to two crimson thrones, embroidered with the initials EIIR and P.

‘We must reproduce those for Elisabetta and Philip II,’ said Tristan in excitement.

‘And keep them permanently at Valhalla after filming’s over,’ giggled Meredith, ‘we can unpick the E and P and change it to R for Rannaldini and H for Hermione, or Helen or Harriet Bussage,’ he added slyly, ‘depending on who’s in favour.’

Rannaldini allowed himself a chill smile, but he could only think of a throne initialled T, with naked Tabitha sprawled on its faded damask, waiting for him to mount the burgundy red steps and her.

In every room there were beautiful clocks depicting heroic scenes. How slowly the minutes must have ticked by for the young Princess Diana, thought Tristan, and for Carlos and Elisabetta. How d’you cure a broken heart in a gilded cage, particularly when every ravishing piece of Sèvres showed idyllic scenes of young shepherds and shepherdesses in love?

‘I want a scrolled codpiece for Christmas,’ said Meredith, bringing everyone back to earth.

‘Her Majesty enters the Throne Room through that emergency exit,’ murmured an official, who’d recognized Rannaldini, ‘so she doesn’t have to walk through a lot of rooms.’

‘That’s nice,’ piped up Meredith, ‘so she can always retreat down the backstairs for a squirt of Diorissimo.’

‘Half the big-looking glasses,’ confided the official, ‘despite being covered with gilt patterns of leaves and flowers, are actually hidden secret doors.’

Rannaldini’s eyes gleamed. How perfect for the to-ing and fro-ing of lovers and Inquisition spies, often the same thing in Don Carlos, and for himself, who liked to vanish like the Cheshire Cat.

They had reached the great spine of the state rooms — the Picture Gallery — mostly Dutch and Flemish masters. Tristan was enraptured and went into a flurry of oh-mon-dieus, particularly over Rembrandt’s Old Shipbuilder and His Wife, whose faces were luminous with affection and inner light. If only Lucy could make the faces of his cast glow like that.

Too much enthusiasm for anything other than himself unnerved Rannaldini, who whisked them past each masterpiece, only pausing to admire Guido’s terrifying painting of Cleopatra being bitten by the asp. Étienne had been the same, thought Tristan, with a pang. As a child he had never been given time to linger over a painting.

‘Christ Healing the Paralytic.’ Consulting the guidebook, Meredith paused before a large oil. ‘He ought to have a go at Tabitha Lovell.’

‘Is she still drinking?’ Tristan tried not to sound interested.

‘Buckets,’ sighed Meredith. ‘She’ll give birth to a little pickled walnut at this rate.’

‘This is the best picture in the room.’ A good-looking official drew their attention to Charles I astride a fine grey horse. ‘His eyes really follow one round the room.’

‘So would mine given the chance,’ said Meredith admiringly.

‘This is the Blue Room,’ purred Rannaldini, ‘where one gathers for drinks before grand diplomatic occasions.’

‘This is it, glorious,’ squeaked Meredith, whipping out his notebook and scribbling frantically. ‘Corinthian pillars the colour of Harrogate toffee, sea-blue flocked wallpaper, masses of gold framing the mirrors and ceiling, pale turquoise sofas, perfect for the Summer Drawing Room and Philip’s pep talk to Carlos.’

Diluting the gilded splendour, through floor-length windows green lawns could be seen sweeping down to a lake surrounded by willows. ‘I’m going to scrap my fences and flower-beds and sweep down to my lake,’ Rannaldini was thinking aloud.

‘Take a lot of mowing,’ chided Meredith. ‘Teddy Brimscombe would give notice and no-one else would put up with you. I like this vermilion,’ he mused, as they moved into the Music Room, ‘like a winter sunset and incredibly flattering to your colouring.’

Rannaldini smoothed his hair complacently, but the smile was wiped off his face when Tristan was suddenly mobbed by a party of French tourists, demanding his autograph, taking pictures and asking after Claudine Lauzerte.

Outraged to lose the limelight for a second, Rannaldini dived under the red rope and played ‘God Save the Queen’ on the Music Room piano. Guides blanched, security men with walkie-talkies rushed in, the French tourists, melting away from Tristan, cheered and clapped as they recognized Rannaldini.

‘I couldn’t reseest it.’

‘That’s OK, Sir Roberto.’

Their last port of call was the White Drawing Room, which took all their breath away.

‘This is answer for the Great Hall,’ exclaimed Rannaldini. ‘Then for Philip’s debate with Posa we can restore our Blue Living Room to its former glory with reds and crimsons.’

‘Isn’t that the room Helen just redecorated?’ said an aghast Tristan.

‘Yes, poor darling,’ agreed Meredith. ‘We tried a hundred coats before we got the right blue. But this gilt and white is to die for. And there’s darling Queen Alexandra over the chimneypiece. She was as good about fat Edward’s philandering as Helen is about yours, Rannaldini, so we might placate her with a new portrait over the fireplace.’