George Henry Robert Charles William Vane-Tempest, 5th Marquess of Londonderry, KP (26 April 1821 – 6 November 1884), styled Viscount Seaham between 1823 and 1854 and known as The Earl Vane between 1854 and 1872, was a British aristocrat, businessman, diplomat and Conservative politician.

His half-brother (by his father's first wife, and therefore not affected by the surname change), Frederick Stewart, became Viscount Castlereagh by courtesy; he later succeeded as 4th Marquess.

In 1823, the 3rd Marquess was created Earl Vane and Viscount Seaham, with remainder to his sons by his second wife.

[6][7] Lord Londonderry managed his father-in-law's estates (see below), which included some of the slate quarries around Corris, Gwynedd, Wales.

They set up home at Plas Machynlleth, the Edwards family seat,[11] and had six children: Lord Londonderry died in November 1884, aged 63.

[14] Lady Frances Anne Emily Vane (1822–1899), sister of the 5th Marquess, married The 7th Duke of Marlborough.

On Lord Herbert's death without issue, a trust set up by his grandmother Frances Anne passed to Winston Churchill, who was his first cousin once removed.