In our latest feature to celebrate The Square Box at the Hill exhibition at Norwich Castle Museum, Trevor Heaton looks at a 'battle' two centuries ago - not between armies... but architects.

Norwich Evening News: Self-taught architect William Wilkins senior is thought to have painted this beautiful watercolour of Norwich Castle in 1795, as a record of its ancient Norman staircase which was about to be swept away.Self-taught architect William Wilkins senior is thought to have painted this beautiful watercolour of Norwich Castle in 1795, as a record of its ancient Norman staircase which was about to be swept away. (Image: Archant)

You can imagine what the Norfolk mothers had been telling their wayward offspring for centuries. 'If you don't behave,' they would scold, 'you'll end up in Norwich Castle!'

While the county's other great Norman castle - Castle Rising - slumbered its way through a bucolic half-life, its Norwich counterpart exercised a lasting and grim hold over the lives and imaginations of Norfolk people.

For after its relatively brief life as a medieval royal palace, this massive building spent hundreds of years as the County Gaol, its unavoidable presence on the city skyline a daily reminder of the perils of trangressing the law.

And if that often-terrifying due process of the criminal law was unavoidable too, then so were the ravages of Anno Domini.

Norwich Evening News: A model of Sir John Soane'’s County Gaol. The celebrated architect's designs were only to last a couple of decades.A model of Sir John Soane'’s County Gaol. The celebrated architect's designs were only to last a couple of decades. (Image: Archant)

The bald fact was that by the late 18th century the ancient building, already almost 700 years old, was fast becoming unfit for purpose. John Howard, a county sheriff who inspected jails and and debtor's houses across England, Wales and Ireland in 1776 on behalf of parliament, found Norfolk's 'men-felons' still housed in a medieval dungeon which often was partially flooded.

Gradually the calls grew stronger for the building to be extended to reflect more modern thinking on housing the county's miscreants. Influential voices such as Norfolk MP Edward Harbord pushed strongly for prison reform. Going to jail, he argued, should be a matter of reform and moral and physical improvement for prisoners.

Their time, he said, should not be 'spent in idleness and debauchery, but in industry and good order'. It was time for the ancient County Gaol to move with the times.

The crying need was for more space, but something more too - security, a healthy environment, plus separation of the sexes and different types of prisoner.

A tall order, but the prison magistrates were confident in their first choice for the architect: William Blackburn, who in his short (40-year) life was the leading prison architect of his time. Ipswich Gaol was one of his projects.

But then along came an even better offer. John Soane was a fast-rising architect with a national reputation, having already worked on such high-profile projects as the Bank of England.

He had also worked in Norfolk before, his several local commissions including a house for Robert Fellowes, one of the prison magistrates. Although he had designed prisons, the County Gaol was to be his first project to actually be built.

From 1789 to 1794 the castle mound saw its busiest building activities since its halcyon medieval days. Buildings around the keep were cleared, including the Governor's House. Inside the keep, remains of the original Norman interior walls were swept away. Gone, too - and this was one of the saddest losses to posterity - was the staircase leading to the Bigod Tower, the original entranceway into the Castle Keep.

In the cleared space within the keep, a freestanding four-storey U-shaped cell block was built. Soane designed it so that it was detached from the ancient walls, allowing the free circulation of air, with the intention, no doubt, of removing one of the perceived causes of the dreaded 'jail fever' (otherwise known as typhus, which was actually spread by lice) - and the stink from the (just two) privies. The male felons were housed here as it was the most secure part of the jail. Two of the cells in the base of the 'U' were for the condemned, shortly to make their one-way walk to the scaffold.

Women prisoners and male debtors were kept in segregated quarters in a new two-storey building alongside the keep. All sections had 'airing courts' where the different categories of prisoners could take exercise.

So, then, problem solved? Not a bit of it.

The building soon came under fire from one William Wilkins Senior, who fumed in 1795 that 'the East front [of the Keep], in which was the grand entrance, is grossly mutilated and entirely hidden by an additional building, that appears to have no kind of connection with it.'

Wilkins knew what he was talking about. Fearing that much of the look of the castle he had known all his life was about to be destroyed, he painted a beautiful and detailed series of watercolours to record it - you can see them in the exhibition, along with Soane's designs - which give us an invaluable insight into the original castle, especially the soon-to-be-destroyed Bigod staircase. Wilkins also produced a classic paper on the Castle in 1796.

Wilkins wasn't finished in his dislike of the new building. In 1811 he goaded Soane again with the comment that his design had created a 'heterogeneous and discordant mass' with the Castle 'bereaved of its ancient beauty.'

(You can get a flavour of what the castle looked at this time in a lovely oil painting attributed to Robert Ladbrooke, which is on loan to the exhibition from Norwich School. It shows the latest changes to the Castle site, with the new gatehouses on the right leading to the resurfaced bridge, all enclosed within cast iron railings.)

Strong words from Wilkins - but just who was he? The Norwich man had originally been a plasterer (following his father's trade, as many did in those days) before becoming a self-taught architect based on Castle Meadow who also managed a chain of theatres.

He had moved with his family to Cambridge in 1780 to better run the theatrical side of the business but clearly felt an emotional 'pull' towards his home city and its historic buildings. His son, also called William, was two years old when the family moved, but was later educated in Norwich.

Soane, stung by the comments of Wilkins Senior, described him as 'an able stuccatore [plasterer]' - ouch - 'who had acquired some facility in drawing, and a smattering of Gothic lore, fancying himself an Architect, felt much disappointed at not having been entrusted with the alterations and additions to the Castle.'

But Wilkins Senior was right. Soane's prison became overcrowded and was also - failing in the first priority for every prison - deemed insecure.

Although Wilkins Senior did not live long enough to see the demise of the Soane building, the family was to have its 'revenge' through this son, William Wilkins Junior. The young man had become inspired by classical antiquities on a three-year tour of Greece, Italy and Asia Minor which was to proved an enormous influence on his later work.

He began his architectural career in 1804, and local commissions including restoration work at Norwich Cathedral (with his father). By 1820 he had created two famous East Anglian landmarks: the Norfolk Naval Pillar (better known as the Britannia Monument to commemorate Admiral Lord Nelson) at Great Yarmouth and Bury St Edmunds' elegant Theatre Royal.

By the time a competition was run to redesign Norwich prison once more - just 27 years after the completion of Soane's buildings - the fast-rising young William emerged as the successful winner of the £100 commission. His buildings (which included a new Shire House at the base of the castle mound, now the Norwich Castle Study Centre on Market Avenue) were built from 1822-27. Wilkins Junior also managed to preserve many of the remaining original features of the castle which had survived Soane's refurbishment, including the re-building of the upper floor of the Bigod Tower.

It's these Wilkins buildings which form the core of today's museum. What were once cell blocks radiating out from a central Governor's House are now galleries. The site of the house is now the Rotunda.

William Wilkins Jr would go on to design many other buildings, most notably the National Gallery in London, but miss out on winning what would have been the crowning glory of his career - the rebuilding of the Houses of Parliament. John Soane, meanwhile, was knighted in 1831, an accolade which was never bestowed on the younger Wilkins.

The Square Box on the Hill, which explores the history of this much-loved and internationally-important building, continues at Norwich Castle Museum until June 3.