Originally from London, where John’s grandfather and namesake traded as an ironmonger,
The subject of this biography already enjoyed a flourishing career in his father’s lifetime, and by the later 1430s, before attaining any public office, he was associating with prominent Kentish gentry like the Cheynes of Shurland. He appears to have enjoyed a close and lasting friendship with Sir John Cheyne II* and their respective arms came to be displayed side-by-side in Minster-in-Sheppey church, suggesting that their families formed bonds of kinship through marriage.
Following his shrievalty, Warner appears not to have played any further significant role in the affairs of Kent until 1449. After witnessing the return of his friend Cheyne and Fiennes’s son-in-law, William Cromer*, to the first Parliament of that year, he himself won a seat in the Commons in the autumn.
It was the outbreak of Cade’s rebellion that had prompted the dissolution of Warner’s only known Parliament, and both Fiennes and Cromer were prominent victims of this serious uprising. Cade’s followers also identified Slegge and Isle as two of ‘the grete extorcyoners’ and ‘fals traytoures’ principally responsible for the oppression of the commons under Fiennes’s malign rule of the county, and a petition submitted to the King during the Parliament of 1450-1 identified the former as one of those ‘mysbehavyng aboute youre roiall persone’.
In the aftermath of the rebellion, Warner’s involvement in Kent affairs increased dramatically. In December 1450 he joined the commission of the peace, a position he would retain until his death, and in January 1451 he was appointed to an ad hoc commission given the sensitive task of attempting to raise a loan in the county. Between his appointment as a j.p. and July 1452, he sat for six days at sessions of the peace, with only the lawyers, Richard Bruyn*, Walter Moyle*, Thomas Burgeys and John Martin, attending more assiduously.
In the same period, Warner was also concerned with important personal matters, for in August 1451 he received a dispensation from Rome legitimizing his marriage to Denise Fynch – probably not his first or only wife – who was related to him in the third and fourth degree. At some point after June 1447, Vincent Clement, a canon of the Kentish college of St. Mary’s, Wingham, had granted the couple a dispensation to marry; but allegations that he had already made more than his statutory 12 dispensations had called his right to do so into question, so prompting the appeal to Rome.
It is likely that Warner died in the autumn of 1460, apparently intestate since Richard and William Bruyn took over the administration of his estate. On 7 Oct. that year, the Chancery issued a writ of clausit diem extremum ordering the escheator in Kent to hold an inquisition post mortem for him, although the records of any subsequent inquiry have not survived.
