Just two months ago, Andrew Mountbatten-Windsor might have convinced himself he was still riding high, nodding and waving at passers-by as he trotted around Windsor Great Park on horseback as though nothing had changed.

But he’d be hard-pushed to believe that now. Today, his former home of Royal Lodge, once a 30-room monument to his status as the late Queen’s favoured son, stands hollowed out, its future uncertain. Its grand rooms have been stripped of elegant furnishings, antiques and art, and of the bustle of footmen, maids and cooks who once kept it running.

And if its disgraced former inhabitant needed reminding of the extent of his downfall, he need look no further than the back garden of his new permanent home on the Sandringham Estate.

Next month, Andrew, 66, will move into Marsh Lodge, a five-bedroom bolthole shielded from public view by a 6ft fence. The reality of his radically altered situation was underlined when he took delivery of a second-hand static caravan a few days ago, which has been propped up on bricks in his back garden, bearing signs of moss.

The man, once second in line to the throne and who had become accustomed to views of Windsor Castle, will from now on gaze at the vehicle, named, with no apparent irony, The Vision.

It is hard not to draw comparisons with Steptoe and Son, the BBC sitcom synonymous with a life reduced – even though the former prince is said to still insist people call him ‘Sir’.

The caravan – a £26,000 Willerby Meridian Lodge – was paid for using money his brother, King Charles, gave him for ‘living expenses’ and it will house his security detail as there is not enough space in his main Norfolk home. It is not a pretty sight – designed in various shades of beige and grey in 2012, it is now faded and dated.

The standard model is a two-bedroom unit that is also decidedly no-frills on the inside. With brown or grey carpets, vinyl flooring, and faux-wood countertops throughout, it also features a compact kitchen with a metal sink and a small, grey-painted living area.

Arguably the standout feature is a chrome-and-glass light fixture hanging from the ceiling; a far cry from the chandeliers Andrew might be more accustomed to.

But the irony is that Andrew appears to be the one person who is not complaining about it.

As one source said: ‘Andrew uses it himself, would you believe, and what’s more shocking is, he likes it. He really is a changed man; he’s enjoyed sitting in the caravan. It’s novel for him.’

Another added: ‘People thought the caravan was for his staff, but he doesn’t really have any. The staff who work elsewhere at Sandringham already help out, but many are reluctant to live in.’

Sources say the caravan, which as a temporary structure is not subject to planning constraints, has been handy for Andrew to use during site visits to Marsh Farm, which is still being extensively renovated in preparation for his arrival.

He is currently living a mile and a half away at Wood Farm, the bolthole of his late father, Prince Philip. Insiders say he is reluctant to leave until Marsh Farm is up to his ‘standards’, to the exasperation of Charles who would like Wood Farm back for ‘overspill’ accommodation for Sandringham guests.

The source added: ‘Marsh Farm has needed rewiring and plastering and there was even talk of asbestos – it’s not in a fit state for him yet. Meanwhile, Andrew wants the best of everything and the process is painfully slow.

‘But he needs to be out soon, and the King would have no qualms about pushing him out of Wood Farm if it was needed for overspill. Andrew might end up sleeping in that caravan if he’s not careful.’

Such speculation has become the subject of amusement in Sandringham. While many staff are appalled that Andrew could not even afford to pay for the caravan himself, some are thrilled that his downfall is so complete.

After all, £26,000 is a relatively small sum for a man who once spent £17 million on a luxury ski chalet in Verbier – something which has not escaped attention.

‘He’s swapped ski chalets for static chalets,’ a friend of his ex-wife Sarah Ferguson grimly remarked. ‘His mother would be turning in her grave to see that monstrosity in his back garden.’

The King, who is known to abhor plastic, might have also preferred to see a tasteful shepherd’s hut – but taste has never been Andrew’s strong point. Sunninghill Park, his former Berkshire home, was likened to a Tesco superstore.

Andrew’s circle once speculated he would spend little time in his Sandringham pad thanks to his billionaire connections – it is said, for example, there is a penthouse waiting for him in Abu Dhabi.

But war in the Gulf means Andrew would be unwise to travel there because he would be a prime target for Iran. A source said: ‘We all thought he’d take the house in Sandringham and then move quickly to Bahrain or Abu Dhabi. Now that’s not going to happen any time soon. He has finally accepted his fate.’

Marsh Farm is a modest red-brick building, a few miles from the main house and a respectable distance from the Prince and Princess of Wales’ home, Anmer Hall. Originally built as a working farm, it was also used as a rental property.

But despite its more modest size, Andrew is said to want to decorate it just like Royal Lodge.

Valuable artworks are being rehung by the nation’s poshest removal firm, Gander & White, which charges around £15,000 for a team. Some pieces are said to be too large for the walls. Undeterred, Andrew has set about rehanging heavy old curtains from Royal Lodge, too, which had to be altered – a considerable expense also covered by the King. A source said: ‘The King is angry because he doesn’t want to pay any more than what he has already.’

Charles has vowed to make ‘appropriate private provision’ for Andrew, though few imagined then that a static caravan would be part of his plans.

Andrew has been laying low since his arrest last month over allegations of misconduct in public office while a UK trade envoy. He was interviewed by police and released under investigation.

But he was recently seen driving near Marsh Farm with a mystery woman in the back seat, perched next to what appeared to be a large box. Other boxes have been pictured arriving bearing the initials ‘HRH’, suggesting he still insists on being known by his former title.

The King agreed to provide him with a home at Sandringham after the Epstein files exposed the true extent of his relationship with the paedophile financier. It understood to be aimed at removing him from public view and ensuring he could be supported privately without further damaging the reputation of the monarchy.

Since his arrival in Sandringham there have been only a handful of visitors – including his elder daughter, Princess Beatrice. His new home is not large enough, however, to accommodate both daughters and their children, should they all visit. ‘Perhaps the caravan would work as overspill for when the princesses come to stay,’ quipped one observer.

These days, Andrew even does his own food shopping. A recent Waitrose delivery to Wood Farm was received by Andrew himself, who carried the bags from the front door and into the kitchen wearing only a dressing gown.

When he finally moves to Marsh Farm life might become more private. But if the move was intended to draw a line under Andrew’s difficulties, it has instead provided a fresh stream of unflattering detail.

A Buckingham Palace spokesperson declined to comment.