It was the only engine in the kingdom.

Joshua Gee, writing in 1731, says: "As we have but one Water Engine in the kingdom for throwing silk, if that should be destroyed by fire or any other accident, it would make the continuance of throwing fine silk very precarious; and it is very much to be doubted whether all the men now living in the kingdom could make another." Gee accordingly recommended that three or four more should be erected at the public expense, "according to the model of that at Derby."[5] The patent expired in 1732.

The year before, Sir Thomas Lombe, who had been by this time knighted, applied to Parliament for a prolongation of the patent.

The reasons for his appeal were principally these: that before he could provide for the full supply of other silk proper for his purpose (the Italians having prohibited the exportation of raw silk), and before he could alter his engine, train up a sufficient number of workpeople, and bring the manufacture to perfection, almost all the fourteen years of his patent right would have expired.
"Therefore," the petition to Parliament concluded, "as he has not hitherto received the intended benefit of the aforesaid patent, and in consideration of the extraordinary nature of this undertaking, the very great expense, hazard, and difficulty he has undergone, as well as the advantage he has thereby procured to the nation at his own expense, the said Sir Thomas Lombe humbly hopes that Parliament will grant him a further term for the sole making and using his engines, or such other recompense as in their wisdom shall seem meet."[6] The petition was referred to a Committee.

After consideration, they recommended the House of Commons to grant a further term of years to Sir Thomas Lombe.