Petre came from an old and prominent English Catholic family, based at Writtle Park, near Chelmsford, Essex, whose peerage dated from 1603. His father’s first wife was a niece of the 9th duke of Norfolk and his half-brother Robert, the 10th baron, married a sister of the 12th duke of Norfolk. His nephew William succeeded as the 11th baron in 1809. On his father’s death in 1801 his mother was appointed as his guardian, and the will instructed Robert to settle on Edward the unspecified ‘estates’ which had been settled on him at the time of his marriage.
Imbued with his family’s Whiggish principles, he became a member of Brooks’s Club at an unusually early age, 6 Apr. 1814. His first known appearance on a public platform was at the Yorkshire county meeting in January 1823, when he admitted that he was a ‘recent convert’ to parliamentary reform, but said he had been alarmed to ‘see the arm of power extended’ in order to ‘oppress’ the people. He was ‘convinced that nothing short of a constitutional reform can restore that sympathy which ... ought to exist between the electors and their constituents, and be an effectual safeguard against a renewal of these destructive measures which have been so long pursued’.
He spoke briefly to confirm the good conduct of the Yorkshire yeomanry, which had been ‘highly instrumental in the preservation of good order’, 27 June 1831. He voted for the second reading of the reintroduced reform bill, 6 July, and generally for its details in committee, but he was in the minority for the amendment to preserve the rights of freemen, 30 Aug. He defended the provision granting six Members to Yorkshire, which would ‘give the different interests ... adequate representation’, 10 Aug. He divided for the bill’s third reading, 19 Sept., its passage, 21 Sept., the second reading of the Scottish bill, 23 Sept., and Lord Ebrington’s confidence motion, 10 Oct. He hoped that the grant to the Kildare Place Society would be considered ‘in the true spirit of Christian charity’, 15 July. He condemned the behaviour of a Catholic priest in county Clare towards the Irish yeomanry as ‘unworthy of any minister of God’, 26 Aug. He protested at the language used by Gordon, Member for Dundalk, in relation to the Maynooth grant and the Catholic religion, 26 Sept., observing that ‘we are not sent here to attack each other in consequence of some minor differences in points of faith, but to do justice to all men and ... promote the interests of all classes in the community’. He warned that rejecting the grant would ‘alienate the minds of the people of Ireland’. He voted to punish only those guilty of bribery at the Dublin election and against the censure motion on the Irish administration, 23 Aug. He became a member of the Maldon Independent Club, the principal organization of the Essex Whigs, 21 Nov. 1831.
He divided for the second reading of the revised reform bill, 17 Dec. 1831, its details in committee and the third reading, 22 Mar. 1832. He opposed Hunt’s motion for inquiry into the Peterloo massacre, 15 Mar., arguing that it would ‘not be wise, or necessary ... to rake up grievances of such long standing’. He voted for Ebrington’s motion for an address asking the king to appoint only ministers committed to carrying an unimpaired reform measure, 10 May. He divided for the second reading of the Irish bill, 25 May, and against the Conservative amendment to increase Scotland’s representation, 1 June. He voted with government on the Russian-Dutch loan, 26 Jan., 12, 16, 20 July, and relations with Portugal, 9 Feb. On the Irish tithes bill, 16 Apr., he expressed confidence in ministers, who were ‘the friends of liberality, and of civil and religious liberty’, and emphasized that he considered the English and Irish churches to be part of the law of the land. Regardless of his personal faith, he felt ‘bound ... by the solemn engagement I have made to support the Protestant establishment’, and would always endorse measures which he thought ‘conducive to the welfare of the Protestant church’. He hoped the bill would ‘soften down religious animosities and place the Protestant clergy upon a safer footing’. He refuted O’Connell’s claim that prior to 1829 the English Catholics would have settled for less than full emancipation, 18 June. He complained about the offensive language used in a Glasgow petition against the Maynooth grant, 10 July, maintaining that ‘we, who are Roman Catholics, are not parties to any such illiberal feelings towards Protestants’. He queried Gordon’s use of the label ‘Arian’ to describe Irish Protestant clergymen who favoured non-denominational education, 23 July. He supported the Norfolk assizes bill, 23 May, arguing that Norwich was the obvious venue on the ground of population. He voted for the ministerial amendment to Buxton’s anti-slavery slavery motion, 24 May, and to make coroner’s inquests public, 20 June 1832.
Ilchester was disfranchised by the Reform Act, but Petre renewed his connection with York, where he was comfortably returned at the general election of 1832. He sat until his retirement in 1834 as ‘a reformer, in general a supporter of the [Whig] administration’, who advocated ‘free trade ... the immediate abolition of slavery, the substitution of a property for the house and window tax, and the abolition of all monopolies’.
