Warrender stood for Haddington Burghs with the support of Sir Hew Dalrymple who wrote to William Mure, 15 Oct. 1766:2Caldwell Pprs. ii (2), p. 92.
I am attacked in my burghs by Lord Lauderdale and in the county by Sir George Suttie ... As I dare not enter into a controversy of burghs at present on account of my entanglements ... I have set up a friend who I can answer for being a good man, and with my assistance will do for Lauderdale.
Warrender, through his friend Sir Alexander Gilmour, obtained Government support.3Dalrymple to Loudoun, 24 Feb. 1768, Loudoun mss. After a double return of Warrender and Lauderdale’s candidate, John Maitland, Warrender’s election was sustained by the House. Throughout his term in Parliament, Warrender was a consistent supporter of Administration, but was absent from the divisions on Wilkes in 1769. There is no record of his having spoken in the House.
At the by-election of 27 Feb. 1771, resulting from Warrender’s appointment as King’s remembrancer in Scotland, he retained his seat against Captain Charles Ogilvie. Alexander Belsches wrote to Lord Balgonie, 19 Apr. 1771:4Leven and Melville Pprs. ed. Fraser, ii. 273.
Colonel Warrender’s election which has been depending for these three days was determined to-day in his favour, though he was in great fears and his adversary had great hopes.
Although Robinson supposed Warrender would come in again in 1774,5Laprade, 8. he apparently resigned his claims in favour of Gilmour; and does not seem to have tried to re-enter Parliament.
He died 14 June 1799.