A hilltop folly was once home to one of the world's great lost libraries, writes Chris Upton.

A three-volume illuminated manuscript – some 450 pages in all – was sold at Sotheby’s in London for £2,100,000 last December. The sales catalogue called it perhaps the finest medieval manuscript still to be in private hands.

The work in question, known as the Rochefoucauld Grail, is a French romance of the High Middle Ages, recounting (and illustrating) the search for the Holy Grail by the knights of King Arthur. Given the price he got for it, the seller – a Dutchman – had no need for the real thing.

We know that the manuscript was originally commissioned by a member of the Rochefoucauld family in 1320 or thereabouts, and had remained in the family until the 1700s. A century later it was snapped by Sir Thomas Phillipps, and it is he who is the subject of this week’s article.

Thomas Phillipps was born in Manchester in 1792, and educated at Rugby and Oxford. Even as a student Phillipps was obsessed with collecting books.

Whilst at Oxford Thomas’s father warned him against attending auctions and spending money he didn’t have. “You will be sorry you have squandered away your property so foolishly,” Thomas senior added.

But Thomas Phillipps came from wealthy stock, and there was always more than enough to squander.

When his father, fearing bankruptcy from his son and heir’s incorrigible spending, placed the Phillipps estate in trust, giving Thomas junior access only to the income, it still provided him with £6,000 a year. Plenty of scope there to visit the bookshops.

Freed from his academic studies, Phillipps could devote himself fully to the project of a lifetime: to collect a copy of every book ever printed.

And this, if anything, was a sideline. It was manuscripts that Phillipps was really interested in. He called himself “a complete vello-maniac”, vellum being the material the best manuscripts were written on.

Where was he to store this impending Alexandria? The Phillipps’ estate was at Middle Hill, close to Broadway in Worcestershire.

Once he got hold of it after the death of his father in 1818, Thomas set about turning the house into the world’s largest private library.

And since it was not always possible to obtain every book and manuscript he wanted, he also set up a printing-press – Middle Hill Press – to reproduce the rest himself. Phillipps recruited a bibligrapher – Adolphus Brightley – to undertake the printing and to produce catalogues of the ever-growing collection.

By then Middle Hill house was already full to bursting. But, as luck would have it, there was a perfect place to set up the press just across the valley, and a short walk from Middle Hill.

And thus one of the most eccentric pieces of architecture in the Cotswolds – the neo-gothic folly called Broadway Tower – became home to one of the most oddball projects in English history. Broadway Tower and Thomas Phillipps were a match made in heaven.

Phillipps’ librarians had to live in the tower too, but the state of the building and Phillipps’ failure to pay their wages, meant that none of them stayed long.