Thomas Tompion was arguably England's greatest watch & clock maker; born in 1639 and trained as a blacksmith (which at the time was the nearest thing there was to an engineer) he became Master of the Worshipful Company of Clockmakers in 1703. He died in 1713 and was the first clockmaker to be given the honour of a burial in Westminster Abbey. This honour was most likely granted because he was watch & clockmaker to two English sovereigns, Charles II and subsequently to the joint reign of William & Mary after the "Glorious revolution" of 1688.

These two sovereigns were his greatest patrons and he, in turn produced his masterpieces for them including one of the first watches with a balance spring for Charles and a series of table clocks for William & Mary culminating in the piece under discussion here: the "Mostyn" year going spring clock.

Made between 1695 and 1700, this magnificent ebony veneered masterpiece is richly decorated with finely chased emblematic silver mounts of crown & crossed sceptres, military trophies, cherub heads and masks. It is hour striking (meaning it sounds the number of hours at each hour) and, on request, quarter repeating and runs for one year on a single winding. Most amazingly, all of this is contained in a clock a mere 28" tall at a time when almost all other year going clocks were just simple timepieces in long cases of over 6' in height.

The clock was one of William's personal favourites and was installed in his private quarters (known as the Royal Bedchamber) and on his death was willed to Henry Sydney, the Earl of Romney who occupied the position of "Gentleman of the Bedchamber". From Sydney it passed through four more members of his immediate family (there seems to have been something of a curse on the Sydney family's ownership of the clock, as the 5 members of the family who owned it all died either unmarried or childless in a period of 56 years) and thence by marriage to the Yonge family and from them to the Mostyn family. It remained with the Mostyns from 1831 until 1982 and they continued the tradition begun in 1793 of keeping records of the annual winding of the clock.

The clock was moved to the family home in North Wales in 1825, where the annual winding ceremony continued. The family home was close to Liverpool where the famed steeplechase "The Grand National" was held each spring from 1839. The Grand National, regarded as the most difficult steeplechase race in the world, became the centrepiece of weekends at the house for many years and around 125 years ago the annual winding ceremony was incorporated into this weekend.

In 1982 the Mostyn family decided to part with the clock and commissioned Christie's to auction the Tompion. The date of Wednesday 14th July was set and the special auction catalogues were printed. The Tompion was in its own catalogue and was scheduled to be sold after the regular watch & clock auction; as is normal with items of such importance the catalogue had no estimate, instead potential buyers were instructed to contact the department for further details. The clock was regarded as a national treasure, and as such, it was unlikely the government would have given permission for its export. This, of course, reduced the number of possible buyers and therefore the potential price; nevertheless suggestions of around £1,000,000 (about $1,600,000) were banded about. However the sale never happened as negotiations behind the scene resulted in the clock being acquired for the nation by private treaty. The final sum paid was never disclosed but it is assumed to be considerably less than the initial suggestions as the Government gave Lord Mostyn undisclosed tax concessions in return.

The clock entered the collection of the British Museum the following year as one of the highlights of their unparalleled horological collection and in 1998 the museum decided to re introduce the annual winding ceremony. So, it was with some delight, that I opened my mail a few weeks ago to find this invitation; in my hand. On the required evening a small party of around a dozen souls turned up at the Museum just as it was closing. In the delightful surroundings of the Pamela Hartwell room we drank a glass or two of wine and exchanged horological gossip whilst trying not to be overawed by the close presence of the world's most valuable clock. Fortunately the museum had had the foresight to display the clock along with the records of its previous windings; I am showing those from 1938 and 1939.

We were invited to wind the clock before the wine got to us; the honour of being first was given to the current Master of the Worshipful Company of Clockmakers. Then John Leopold (the previous head of Horology at the BM) gave it a wind (the gentleman with the medal is the Master). I was then invited to come forward and have my turn at the crank, I then realised why this clock could run for 12 months, winding this clock was like cranking a vintage car. It required substantial effort and a significant number of turns to provide the necessary power for the massive movement with its two sections, going and striking.