Starlight Castle is a folly on the grand Seaton Delaval estate close to the Northumberland coast. Today only a small section of wall survives, and historic photographs and postcards show it already in ruins a century ago. It was probably built by Sir Francis Delaval (1727-1771) in the middle of the 18th century. The story goes that Delaval wagered he could build a castle overnight, and this was the result.

Sir Francis supposedly won his wager, and hence the building was named Starlight Castle. He was  known as a practical joker and remembered as ‘the very soul of frolic and amusement’. There are tales of guests being tipped from their beds into cold baths, or exposed in undress when walls turned out to be curtains. With gentler humour he kept a ‘flock’ of carved stone sheep in front of the mansion which a visitor in 1752 said ‘would deceive anybody til very near’. So such a bet seems perfectly in character – but that so substantial a structure could have been constructed by moonlight seems most unlikely, and the story looks a bit shaky when it transpires that 18th century accounts refer to ‘Starling Castle’ (1774) or ‘Sterling Castle’ (1791).

An 1811 account noting the ‘Seaton Delaval Summer House’, probably refers to the sham castle. It stands on high ground in the picturesque Holywell Dene (dene being the local name for the deep wooded valley of a stream – in this case the Seaton Burn, burn being the Northumberland name for a stream). Built as a destination for picnics, it commanded extensive views out to sea, and would have been a pretty diversion on a drive around the mansion’s pleasure grounds, which also included a prominent obelisk and a grand mausoleum, both of which survive today, the latter in a poor condition.

The view would also have included the industrial-picturesque scene of the Delaval bottle-works by the bustling port. The Delaval family controlled the harbour at Seaton Sluice, a natural inlet which was developed to allow access for the large boats which transported the coal mined on the Seaton Delaval estate. The latest science and technology used by the Delaval family to control the water in the harbour, as well as their coal and glass industries, made the area an attraction for enlightenment tourists (sadly none of them seem to have left an account of the little castle). The folly would have provided great views of boats approaching the harbour, and of the myriad ships heading for the mouth of the Tyne, just a few miles south. It would also have acted as an eye-catcher from the harbour, framed by the steep banks of the Holywell Dene.

By 1841 it was a dwelling house and is named in the census as ‘Starling Castle’. A decade later the census records yet another variant spelling as ‘Stirling Castle’ and this is how it is marked on the first Ordnance Survey maps surveyed from 1858. The OS surveyors working on that map described it as a cottage with ‘parapets’ on the east, west and north sides which gave it a ‘castellated appearance’. They were told the tale of the wager, and carefully noted it in their account of the building.

Throughout the 19th century the Delaval family allowed public access to Holywell Dene (apart from occasional closures in protest at vandalism), and it was a much visited tourist attraction. In 1867 Mr Robert Lowrey of nearby Earsdon took an advert in the local paper to announce his fine line in refreshments (PIC-NICS! TEAS!! PIC-NICS!!! shouted the headline) for visitors to beauty spots such as ‘Starling Castle’, and when a new railway station was proposed for Holywell Dene in 1908, it was noted that it would make it easy to walk to the folly ‘with its romantic traditions’.

By 1925 the folly was described as being ‘completely in ruins’. The two front towers were still standing to their full height, but that on the right had separated from the central block, and had an alarming lean that suggested its days were numbered. As the images here show, that was indeed the case, and only a consolidated fragment survives today. Until fairly recently the vegetation around the folly was kept low and it was possible to appreciate the view to Seaton Sluice harbour, but today the remains are engulfed in trees in the growing season.

There is a popular public footpath though Holywell Dene from Seaton Sluice harbour. Seaton Delaval Hall and grounds are in the care of the National Trust and are currently undergoing major renovations. You won’t get thrown out of bed, but you can still find the stone sheep. https://www.nationaltrust.org.uk/seaton-delaval-hall

Update: This charming watercolour, looking along the burn to the folly, was one of a number of views of Holywell Dene and Seaton Sluice sold at Anderson and Garland salerooms in Newcastle in December 2025.

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