Corbet’s political life lies mainly beyond the scope of these volumes as he did not become active in either local or national affairs until after 1628, when his elder brother Sir John, one of the ‘Five Knights’, died as a result of being imprisoned by the king. John’s death may ultimately have influenced Corbet to become a staunch parliamentarian during the Civil War.
An active lawyer, Corbet was returned to the 1628 Parliament as the junior burgess for Great Yarmouth, where he was recorder.35 Norf. RO, Y/C19/6, f. 89v; Y/C18/6, f. 242v. He was named to four private bill committees. These concerned the lands of Samuel Sewster (16 May) and Edmund Hammond (16 June); the granting of Sir Walter Raleigh’s† estate of Sherborne to George Digby, earl of Bristol (23 May) and the restitution-in-blood of Raleigh’s heir, Carew† (28 May).36 CD 1628, iii. 429, 558; iv. 3, 331. Corbet seems also to have been interested in a petition submitted by the bookseller Michael Sparkes against High Commission, as he was required to help examine it on 20 May and on 3 June presented it to the Commons.37 Ibid. iii. 492; iv. 68. In the 1629 session Corbet’s committees included bills concerning the begging of forfeitures before attainder (23 Jan.); the reversal of a Court of Ward’s decree against John Estofte (19 February) and petitions from William Nowell* (7 Feb.), Mr. Billingsley (13 Feb.) and John Rolle* (20 February).38 CJ, i. 927a, 929b, 931a, 931b, 992a; CD 1629, pp. 177-8.
Corbet became an important Member of the Long Parliament, was a founding member of the Eastern Association, and later signed the death warrant of Charles I. Appointed a commissioner for Irish affairs in 1650, he lived in Ireland during the 1650s, becoming chief baron of the Irish Exchequer in 1655. After the Restoration, he was elected for Great Yarmouth to the Convention Parliament, but his return was annulled. Fearing retribution for his part in the regicide, Corbet fled to the Continent, but was captured in Holland by Sir George Downing† and brought to England, where he was tried and condemned to death.39 Oxford DNB; M.F. Keeler, Long Parl. In his scaffold speech on 19 Apr. 1662, Corbet claimed that he had always acted on behalf of the lawful authority of the state. He also declared that he still maintained the ‘Congregational way’ in religion.40 W. Kennet, Reg. and Chronicle Ecclesiastical and Civil, i. 664-5. No will or letters of administration have been found.41 LR2/266, ff. 1, 7.