ROBERT HARDMAN goes inside the tiny Windsor Castle chapel where baby Archie will be christened

Standing at opposite ends of Windsor Castle, they are two places of worship which could hardly be more different. In the Lower Ward stands one of the most famous churches in the world: St George’s Chapel, Gothic medieval masterpiece, spiritual home of England’s patron saint and resting place of sovereigns.

It was there, just over a year ago, the Duke and Duchess of Sussex took their vows in front of the Queen, 600 guests and an estimated global audience in excess of one billion people.

Today, though, the couple will head for the Upper Ward and Windsor’s other house of God for the christening of their son, Archie, by the Archbishop of Canterbury, behind firmly closed doors.

The Private Chapel (pictured), as its name suggests, is not on the tourist trail. It is a royal inner sanctum so intimate that it seats just a dozen worshippers. When the Queen wants to commune with the Almighty alone, this is where she comes

The ceremony will take place in front of just a handful of close family and friends in a chapel which few outsiders have ever seen.

For the Private Chapel, as its name suggests, is not on the tourist trail. It is a royal inner sanctum so intimate that it seats just a dozen worshippers (though a few extra seats may be added today). When the Queen wants to commune with the Almighty alone, this is where she comes.

Like every part of this great Norman fortress, the chapel has a fascinating history, except, in this case, it is a surprisingly short one.

Despite the 16th-century masterpiece hanging over the altar and the knight in shining armour peering down from a pedestal, this room dates back a mere 27 years — and the Duke of Edinburgh’s imprint is all over it.

For until 1992, this was a passageway between the public and private parts of the castle. The original Private Chapel was just round the corner.

But all that changed on November 20, 1992, one of the darker days in Windsor Castle’s 1,000-year history.

It was in the chapel that an overheated lamp set fire to a curtain. It caused an inferno which raged day and night through some of the oldest and most important rooms in Britain, illuminating the night sky for miles around.

It all changed on November 20, 1992, one of the darker days in Windsor Castle's 1,000-year history. It was in the chapel that an overheated lamp set fire to a curtain. It caused an inferno (pictured) which raged day and night through some of the oldest and most important rooms in Britain, illuminating the night sky for miles around

It all changed on November 20, 1992, one of the darker days in Windsor Castle’s 1,000-year history. It was in the chapel that an overheated lamp set fire to a curtain. It caused an inferno (pictured) which raged day and night through some of the oldest and most important rooms in Britain, illuminating the night sky for miles around

Coming on the back of various royal marital woes, it was the final straw for the Queen who shortly afterwards called 1992 her ‘annus horribilis’.

Windsor would be reborn, though, even more stately than before. It was the Duke of Edinburgh, supported by the Prince of Wales, who oversaw the five-year £36.5 million restoration. Britain’s finest craftsmen and women were commissioned to help rebuild the great apartments, including the most important room, mighty St George’s Hall with its hammerbeam roof made from 70 oaks. But perhaps the most radical redesign was the Private Chapel, where the Royal Family gather today.

Few mourned the loss of the old Private Chapel in the blaze. It had been a rather severe and gloomy Victorian space where Prince Charles liked to sneak in as a boy and deliver sermons to imaginary congregations.

In the Seventies it had been done up in golds and yellows by Sir Hugh Casson, the interior designer responsible for the Royal Yacht Britannia’s decor, but remained what one architectural historian called ‘an ungainly elbow between the Private Apartments and the State Apartments’.

Today, the Duke and Duchess of Sussex (pictured) will head for the Upper Ward and Windsor's other house of God for the christening of their son, Archie, by the Archbishop of Canterbury, behind firmly closed doors

Today, the Duke and Duchess of Sussex (pictured) will head for the Upper Ward and Windsor’s other house of God for the christening of their son, Archie, by the Archbishop of Canterbury, behind firmly closed doors

The Duke of Edinburgh and his restoration committee decided to switch things around in this corner of the castle.

The old chapel would be transformed into a new passage linking public and private quarters.

Now called the Lantern Lobby, it has a plaque marking the spot where the fire had started. The old passage, meanwhile, would become the new chapel.

Giles Downes, the architect behind the restoration, was asked to come up with designs.

The art critic Brian Sewell delivered a typically sulphurous verdict. ‘The chapel is to be a dinky little thing which could as well serve the purpose of a cheap Italian restaurant,’ he sniffed, adding that it was ‘meagre in its scale and wretched in its feeble detail’.

The result, however, was a stunning timber umbrella of soaring, curving oak ribs which Adam Nicolson, the official historian of the castle restoration, has called an ‘extraordinary, continuous and closely moulded net of tracery’. It is certainly a very intricate ceiling for a rather small room.

The chapel has no pews. Instead, it is filled with chunky giltwood chairs which were originally commissioned by George IV for the State Dining Room and then rejected for being too heavy. Nearly two centuries later, they have found their role.

The new chapel needed a new altar (the old one having been incinerated) and the Queen’s furniture-making nephew, Viscount Linley, was invited to build it.

The altarpiece hanging above it is Berto di Giovanni’s Virgin And Child Enthroned. Painted in Perugia, central Italy, while the Tudors reigned in England, it entered royal ownership in the 19th century when it was acquired by Queen Victoria.

Its vision of baby Jesus clasping the Virgin’s thumb is certainly an appropriate one for a baptism. Yet this chapel has no font.

So, the Sussexes will borrow the Lily Font from the Jewel House at the Tower of London. Made of silver gilt, it was commissioned by Queen Victoria for the baptism of her first child in 1841. Adorned with three cherubs, it looks like a giant punch bowl and has been used at most royal christenings ever since.

Most striking, however, is the great stained glass window which dominates and illuminates this chapel.

Most striking, however, is the great stained glass window (pictured) which dominates and illuminates this chapel

Most striking, however, is the great stained glass window (pictured) which dominates and illuminates this chapel

The six-part design was sketched by Prince Philip. He wanted the lower panels to show the wreckage of the fire either side of the dragon — representing evil — being slain by St George.

The upper section would show a sunlit Windsor Castle rising from the ashes, with the Holy Trinity looking down approvingly from on high.

The Duke handed his very detailed sketch to glass designer Joseph Nuttgens who brought it to life in dazzling detail. On the bottom right, we see Windsor Castle’s Brunswick Tower bursting into flames while a fireman tries to bring it under control.

The six-part design of the window (pictured) was sketched by Prince Philip. He wanted the lower panels to show the wreckage of the fire either side of the dragon — representing evil — being slain by St George

The six-part design of the window (pictured) was sketched by Prince Philip. He wanted the lower panels to show the wreckage of the fire either side of the dragon — representing evil — being slain by St George

On the left, a workman rescues a portrait from the wreckage. It is of Sir Jeffrey Wyatville, the Georgian architect who remodelled much of Windsor Castle and is buried there.

This panel is a reminder of the human chain which saved so many works of art. It was one of the minor victories from the 1992 fire (the Duke of York was one of those involved). Nearly all the Windsor artwork was saved.

However, there was one treasure too big and too heavy to move before the rafters came crashing down in the Grand Reception Room.

It is just a pity that the man who has played such a key role in its creation will not be there this morning. The Queen and Prince Philip have prior commitments in Norfolk while Archie (pictured with Meghan and Harry on May 8) is christened

It is just a pity that the man who has played such a key role in its creation will not be there this morning. The Queen and Prince Philip have prior commitments in Norfolk while Archie (pictured with Meghan and Harry on May 8) is christened

Note that big green pot in the lower left window. It is the two-ton malachite urn — 5ft wide and taller than a man — which Tsar Nicholas I gave Queen Victoria in 1841. It wouldn’t budge.

In the centre, St George is slaying the dragon as it breathes its last flame. Up above, all is sweetness, light and resurrection.

The Duke is modest about his contribution. In 2005, he showed me round Windsor for The Queen’s Castle, a BBC documentary which I was writing.

He was happy to show me the chapel, but was reluctant to take the credit. I complimented him on his stained glass window and he quickly replied: ‘It’s not mine.’

Eventually, though, he accepted that it sort of was. ‘Well, I suggested the general idea, yes,’ he admitted. ‘The idea was that the bottom was the fire and firefighters. We thought we’d put in a portrait of Wyatville, who’d been architect here, and the idea was the smoke would turn into trees and show the castle remerging in the sunlight.’

The chapel also includes one figure salvaged from wreckage of the old — the statuette of a knight in armour. ‘That’s St Michael up there,’ the Duke explained with a chuckle. ‘He lost his arm. He was the only survivor. We thought we’d leave him the way he was but he looked a little uncomfortable without any arms!’ So St Michael was given new limbs.

This chapel is a gem, a reminder of the way that the British monarchy has reinvented and rejuvenated itself over the centuries.

It is just a pity that the man who has played such a key role in its creation will not be there this morning.

The Queen and Prince Philip have prior commitments in Norfolk.

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