Blackburne, who represented his native county for 46 years, gave general support to Pitt, from whom he obtained the wardenship of the Manchester Collegiate Church for his brother in 1791.
Blackburne, who on 22 Feb. 1804 aired the grievances of journeymen calico printers, adhered to Addington after his fall from power and was marked ‘doubtful’ by Pitt’s second ministry in May 1804. Despite his vote against the additional force bill, 11 June, he was listed under ‘Pitt’ in September, but the following month he wrote to Addington criticizing his successor’s financial measures. When seeking leave from Addington in December 1804 to miss the opening of the forthcoming session, he expressed the hope that a reconciliation with Pitt was in the offing, ‘as I think myself and the public would feel great confidence in the addition of your patriotism and integrity to the public councils’, and he duly rejoiced in the junction when it took place the following month. He reported from the committee of the whole House on the corn trade regulation bill, 28 Jan. 1805, but no other trace of activity in that session has been found and it was from Cheltenham that he replied to a letter from Addington (now Lord Sidmouth) in July, when ministers listed him under ‘Sidmouth’, informing him of the final rift with Pitt: ‘Whatever is your situation you will always possess my friendship and true esteem and I shall ever recollect with conscious satisfaction that I was a firm supporter of the most upright administration I have ever remembered’.
Blackburne was present at a meeting of ‘Pitt’s friends’ to consider the steps to be taken over his funeral honours in January 1806,
Opposition hopes that Blackburne would vote with them against the address, 26 June 1807, were not realized and although he was said to be ‘furious against the seizure of the Danish ships’ in December, he did not vote against government on the issue in February 1808.
The Liverpool ministry, of which Sidmouth was a member, listed Blackburne among their supporters and he voted with them in 8 of the 23 divisions of the 1812 Parliament for which full lists have been found, including those on the renewed suspension of habeus corpus, 23 June 1817, and the employment of spies, 5 Mar. 1818, when he refuted allegations made in a hostile Manchester petition. He paired in favour of the Irish window tax, 21 Apr., and spoke and voted against Bennet’s motion on the imprisonment of radical booksellers, 21 May 1818. His only known wayward votes were on the sinecure bill, 29 Mar. 1813, the civil list, 8 May 1815, and the property tax, 18 Mar. 1816, and he voted with the minority on the Speakership, 2 June 1817. He presented petitions against the corn bill, 6 Mar. 1815, but is not known to have opposed the measure. In October 1816 he asked Sidmouth to station a troop of cavalry at Blackburn in case of disturbances.
As Blackburne aged, he became eccentric. Captain Gronow recorded a visit to Hale in 1815:
Mr Blackburne was extremely absent and otherwise odd: upon one occasion I gave him a letter to frank, which he deliberately opened and read in my presence; and on my asking him if it amused him, he replied that he did not understand what it meant.
Gronow went on to tell how Blackburne peremptorily refused to shoot with the Duke of Gloucester because he carried his gun cocked, repeatedly drained his royal guest’s wine glass at dinner and afterwards deprived him of his cup of tea, pursuing the royal servant who held it and brushing aside his protestations with the exclamation, ‘D— his Royal Highness; I will have this tea.’
