Keyt was descended from an old Gloucestershire family, who acquired their Warwickshire estates by purchase in the seventeenth century. In 1715 he was turned out of the commission of the peace for proclaiming the Pretender, to whom his name was sent in 1721 as one of the chief Warwickshire Jacobites.
There has been above £3,000 spent on both sides at Warwick. Sir William Keyt, who is returned, is a Tory indeed; barring that, I hear a mighty good character of him in all respects.
HMC Portland, vii. 368-9.
He sat for Warwick, voting against the Government, till 1735, when he was unseated on petition.
Keyt subsequently left his wife to live with her maid on his Gloucestershire estate, where he impaired his fortune by extravagant expenditure on building. When his mistress, viewing his house, asked ‘what is a kite without wings’, he added two large side extensions to it. Deserted by her, he took to the bottle. Setting fire to his house after a prolonged drinking bout in September 1741, he perished in the flames, resisting attempts to rescue him.