On his return to England, the king Edward III committed the great seal, which had been alternating between Archbishop John de Stratford and his brother Robert de Stratford, the Bishop of Chichester, to Bourchier, who thus became, on 14 December 1340, the first lay chancellor. His salary was fixed at £100, besides the usual fees. In the struggle between the king and the archbishop, Bourchier withheld the writ of summons to the ex-chancellor, interrupted his address to the bishops in the Painted Chamber, and on 27 April 1341 urged him to submit to the king. When the parliament of 1341 extorted from the king his assent to their petitions that the account of the royal officers should be audited, and that the chancellor and other great officers should be nominated in parliament, and should swear to obey the laws, Bourchier declared that he had not assented to these articles, and would not be bound by them, as they were contrary to his oath and to the laws of the realm. He nevertheless exemplified the statute, and delivered it to parliament. He resigned his office on 29 October 1341. Robert continued to serve in the King's Council, as a diplomat and as a soldier. In 1342, he commanded a contingent in Brittany, and is recorded as being at the Battle of Crécy in 1346.