‘Beau’ Lascelles succeeded his father as Member for Northallerton on the latter’s elevation to the peerage. Unlike his brother Henry, who was returned for the county at the same time, he had no taste for politics: he had ‘a very great aversion to offer himself for the county’. The family were committed to support of Pitt’s administration and his was silent. When he visited Paris in 1802, the French summed him up: ‘Milord Henri Fitzgerald loue tout, Monsieur Greville dit mal de tout et Monsieur Lascelles ach‘te tout’.
At the election of 1807 Lascelles was returned both for Northallerton and Westbury, vacating the latter in favour of his brother, who was defeated in the county election. The seat was evidently purchased as a security for Henry. He was listed ‘against the Opposition’ by the Whigs in 1810, voting with ministers on the address, 23 Jan., and on the Scheldt divisions of 26 Jan., 5 and 30 Mar. He voted against the discharge of the radical Gale Jones, 16 Apr., and against sinecure reform, 17 May 1810. He was in the government minority on the Regency division of 1 Jan. 1811 and again on Stuart Wortley’s motion, 21 May 1812. He appeared on the Treasury list as a supporter after the election of 1812, but his only known vote in that Parliament was against Catholic relief on 24 May 1813. Lascelles died v.p. 3 June 1814.
He was a handsome man, rather inclined to be fat, which gave him a considerable resemblance to George, Prince of Wales, whom he evidently imitated in his dress and manner ... His house though not large, was a museum of curiosities selected with great taste and judgement ... His life was luxurious but short, as he died at the age of fifty.
Raikes Jnl. iii. 184-5.