Surrounded by a twentieth century housing estate in south London, this classical building comes as something of a surprise. The Orangery, as it is known today, was once a feature of the pleasure grounds of Robert Thornton’s house on the edge of Clapham Common.

Thornton (1759-1826), an MP and businessman, had inherited a substantial fortune from his merchant father, John Thornton (1720-1790). Robert’s house stood in a small landscaped park with lakes, and in around 1792 he added this elegant building. Over the door is an inscription from Virgil which gives a clue as to the purpose of the fine structure: HIC VER ASSIDUUM ATQUE ALIENIS MENSIBUS AESTAS, which translates as ‘Here is eternal spring and summer in months not her own’, or ‘Tis here eternal spring and summer all the year’: the building was a greenhouse, where tender plants could be kept alive in the colder months of the year.

The artist Joseph Farington visited in 1806, with his friend William Wilberforce, and noted in his diary that the Orangery was built to a design by Dr Burgh of York. William Burgh (1741-1808) was Irish-born, but lived in York for many years. He doesn’t seem to have a history as an amateur architect, but he was a friend of the poet and garden designer William Mason, and wrote a commentary to accompany the 1783 edition of Mason’s poem The English Garden. In this text Burgh wrote that Mason’s lines about a greenhouse ‘where rare and alien plants/might safely flourish’ was inspired by the French writer and landscape designer René Louis Girardin. Girardin published De La Composition des Paysages in 1777, in which he suggested that a greenhouse with a background of trees would form a ‘jolie tableau‘. Girardin’s concept and Mason’s lines were brought to life in Clapham.

Long since lost is a marble tablet which was inside the building. It was inscribed with an extract from William Cowper’s poem The Task, including these lines which echo the quotation from Virgil on the frieze:

Unconscious of a less propitious clime,
There blooms exotic beauty, warm and snug,
While the winds whistle, and the snows descend.

The pediment is decorated with what are believed to be Coade stone ornaments. In the engraving (above) the central plaque appears to feature a profile, but if that was the case it has disappeared, and it is not known who or what it represented (by the mid-20th century the oval space was a window which lit the attic behind the pediment). The Greenhouse, as it was originally known, had a view of a serpentine canal and lawns and then over a haha to the meadows and another serpentine lake beyond. The Greenhouse was originally furnished with huge sash windows, with curious glazing between the columns – rather like stretcher bond in brickwork (see the photo’ below).

In 1808 Queen Charlotte, the Princesses and the Dukes of Cumberland and Cambridge visited the Thorntons at their ‘Clapham Villa’, and were shown the Greenhouse, but soon after Thornton got into financial difficulties. The Thornton Estate was offered for sale in 1810 when it was described as a ‘most superb villa’ with gardens full of native and exotic species ‘now in the highest state of cultivation’. The map in the sales particulars shows the ‘Greenhouse’ overlooking one of the serpentine lakes.

The estate was on the market again in 1851 when the ‘beautiful conservatory of Portland stone’ was described as ‘commanding views over the pleasure grounds and rich meadow land, which presents the appearance of a small park’.

The estate was bought by a Belgian order of nuns who established the Notre Dame convent and school on the site. New buildings were added, playing fields and tennis courts were laid out, and the girls could row on the serpentine lake and ride ponies in the grounds.

The convent closed in 1939 but its name lives on in the Notre Dame Estate, which was developed on the site of the convent and former Thornton gardens soon after the Second World War.

All that remains today of the pleasure grounds is the Orangery, which serves as an elegant backdrop to a recreation ground in the middle of the Notre Dame Estate. In the early 1950s the writer E.M. Forster, whose great-aunt Marianne was a Thornton, visited Clapham and found ‘no Thornton memorial except a dilapidated Orangery’. He was saddened that the site had been cleared ‘at a time when development was unusually ruthless’.

Unsurprisingly, the windows were the first casualty when the building stood empty, and today the rather forlorn building stands behind security fencing.

The Orangery has been largely without a purpose since the estate was constructed. Drawings by the Borough of Wandsworth Engineer, Surveyor and Architect show that the building was consolidated in 1955 when it was listed at Grade II, and it has had occasional remedial works ever since. The Orangery is on Historic England’s Buildings at Risk Register and, despite much debate and local support, a viable future for the structure remains to be found.

Update October 2025: Private Eye’s architecture correpsondent, ‘Piloti’, wrote about the orangery in the edition dated 17-30 October 2025. More than half of the roof has collapsed and Lambeth Council are seeking external funding to pay for repairs estimated to cost £100,000.

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By the early 18th century Hornby Castle was a seat of the D’arcy family, earls of Holderness. Robert D’arcy, the 4th earl, began to improve the estate from around 1750 with John Carr of York remodelling the castle and associated buildings, including three eye-catcher farmhouses to be viewed from the castle and the network of rides around the estate. Capability Brown was paid for his services in 1768 and although it’s not known exactly what he proposed, as no plan survives, the series of lakes in a very Brownian style were constructed over the next decade.

Before Brown, an amateur, or gentleman designer had made his mark on the gardens. D’arcy’s friend, the Revd. William Mason, was Rector of Aston, near Sheffield, another of the earl’s seats. Mason gave advice on garden design at a number of sites and found wider fame when he published the poem The English Garden in four volumes from 1772-81. In 1760 Mason recruited another of his circle, Richard Bentley, to design a garden ornament for a spot he had chosen at Hornby. Bentley was a member of Horace Walpole’s ‘Committee of Taste’, a group of men admired for their style and good taste (they’d probably be ‘influencers’ on instagram today). Mason had sent a rough sketch but as he did not ‘pretend to much skill’ he asked Bentley and Walpole to tickle up his design. D’arcy was impressed with the ‘very pretty Gothic room’ and ordered work to start immediately.

By 1762 the building was nearly complete and William Peckitt of York supplied stained glass for the windows and a panel over the door where D’arcy’s motto ‘Un Dieu, Un Roi’ accompanied the family crest. The Italian Stuccadore Cortesi worked on the compartmented ceiling; he was probably brought to the project by John Carr who managed the works (D’arcy wrote that his friend Carr ‘had the overlooking of all’ his building works in Yorkshire).

The building takes its name from the Bowling Green that was close by but its primary function was as a banqueting house. Furnished with 18 chairs and two square dining tables the neighbouring gentlemen were invited to dine in the building every Monday. A local inn delivered the food and ‘Strangers of genteel appearance were admitted without restraint’.

Sometime in the 19th century, when these evenings of bonhomie had come to an end, the Bowling Green House became home to an eclectic collection of artefacts from around the world. The Museum, as it was known, was fitted out with glazed gothic cabinets, and housed arms and armour, grand tour souvenirs, ethnographic and natural history collections and celebrity memorabilia such as Lord Byron’s cane.

Hornby Castle passed by marriage to the dukes of Leeds in 1778, and remained in their hands until 1930 when they decided to disperse their Yorkshire estates. The contents of the castle, including The Museum’s collection, were sold at auction and the estate was bought by a speculator who was only interested in the land. Having tried, and failed,  to sell the castle at auction he announced a demolition sale. At the eleventh hour it was agreed that a more manageable portion of the castle could remain ‘and thus continue to be a landmark’. Although the fabric of The Museum was marked up into several lots for sale it too won a reprieve, and was allowed to stand.

The building is now roofless, and the front elevation has partially collapsed, but the other walls are largely intact. It is Grade II listed and one must hope its future can be secured. Hornby Castle is private but the rear elevation of the Bowling Green House can be glimpsed from a footpath, especially when the trees are bare. There are also occasional openings in aid of charity.

The Architectural and Archaeological Society of Durham and Northumberland have been investigating Hornby Castle for a number of years and their fascinating discoveries can be explored here http://www.aasdn.org.uk/hornby.htm