Preston passed much of the rest of his life in prison. He died in The Clink prison, 5 April 1640. In one prison or another he wrote, under the assumed name of Widdrington, several works treating of the oath of allegiance. Preston "evermore disowned" the books written under the name of Widdrington, but there is no doubt that he was the author of them. Towards the end of his life, however, he seems to have altered his views, or at any rate to have made full submission on the question of the oath to the authorities of Rome.