Sir Thomas, like his father, may also have fought on the Lancastrian side at the Battle of Tewkesbury, but was granted a pardon after paying heavy fines.
In the 1484 Parliament of Richard III, he was attainted and deprived of his estates, which were bestowed on his stepsister Anne's husband, Sir James Tyrell, the suspected murderer of the two young princes in the Tower.
Katherine, Thomas' wife was granted an annuity of £100 from the forfeited estates, originally belonging to the Dynham family.
On the ascension of Henry VII, the attainder was reversed and the estates restored but the restitution was too late for Thomas who died 11 October 1485, just a few weeks after the Battle of Bosworth.
In addition to the Cornish properties and other inherited from Sir John Chideock in Dorset, he held four manors in Devon.