Sir Thomas Lawrence, 'Portrait of the Hon. Emily Mary Lamb', 1803

Lawrence has depicted the 16-year old Emily Lamb as though in motion, her head turning back towards the viewer. Her lips are slightly parted as though she is about to speak to us. The pose is one with a long tradition in the history of portraiture, but Lawrence has treated it with a freshness reflected in the informality and economy of his brushwork. The dynamic, fleeting pose and sketchy brushwork capture the spirited young girl whom her brother William called ‘that little devil Emily’.

Prior to its acceptance by the National Gallery under the Acceptance in Lieu scheme, this intimate portrait had never been on public display, having always remained with the sitter’s descendants. In contrast to the Gallery’s other more formal and full-length portraits by Lawrence, such as Queen Charlotte, John Julius Angerstein, aged about 55 and John Julius Angerstein, aged over 80, this portrait exemplifies Lawrence’s influential and more informal portraits of families and children.

Emily was born in 1787 to Peniston Lamb, 1st Earl Melbourne, and his wife Elizabeth (née Milbanke). The couple are portrayed in Stubbs’s The Milbanke and Melbourne Families of about 1769, which is also in the Gallery’s collection.

At the age of 18 Emily married Peter Leopold Clavering-Cowper, 5th Earl Cowper, and went on to become an influential, politically prominent society hostess. Emily was one of the patronesses of the highly exclusive Almack’s club in London, which admitted both ladies and gentlemen and held balls on Wednesday evenings. She was noted not only for her beauty but also for her extraordinary charm and joyousness.

Emily had five children – three boys and two girls. Henry John Temple, 3rd Viscount Palmerston, was a regular guest at Emily’s parties and salons, and as Emily’s husband Lord Cowper became increasingly unwell, Lady Cowper and Lord Palmerston became lovers. In 1837, Lord Cowper died, leaving the way open for Emily and Palmerston to marry. However, Emily’s family considered their ages a problem and the matter was referred to Queen Victoria. Palmerston was 55 and Lady Cowper was 52 when they married on 16 December 1839. Lord Shaftesbury said: ‘His attentions to Lady Palmerston, when they both of them were well stricken in years, were those of a perpetual courtship. The sentiment was reciprocal; and I have frequently seen them go out on a morning to plant some trees, almost believing that they would live to eat the fruit, or sit together under the shade.’

Lord Palmerston served twice as Prime Minister between 1855 and 1858 and again from 1859 to 1865. Emily’s brother, Viscount Melbourne, also served as Prime Minister (in 1834 and from 1835 to 1841).