Warrender stood for Haddington Burghs with the support of Sir Hew Dalrymple who wrote to William Mure, 15 Oct. 1766:
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.
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:
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,
He died 14 June 1799.
