In December 1883 Beatrix Potter, then seventeen, was taken by her father to call on John Brett at his London studio in Harley Street. The painter, whom she described in her journal as, ‘such a nice kind hearty little man, stout with dark red whiskers’, had spent June to October that year sailing the British coastline on his new purchase, the schooner Viking, and the studio was crowded with works from the season. Potter recorded his working method exactly: small oil sketches taken at sea in summer were translated into finished pictures during the winter months, ‘chiefly from memory, though assisted by photographs, for he is a successful photographer’. She added a piece of professional gossip: ‘Mr. Millais says all artists use photographs now.’ (Leslie Linder (ed.), The Journal of Beatrix Potter, 1881-97, London, 1966, p. 65). Given the relative size of the present work, it is likely to have been one of the pictures in his studio when Potter visited.

A keen sailor, Brett bought the 100-foot Viking so that he could take his wife and six children (to be seven in 1884) on long summer holidays, which would also serve as a floating studio and enable his passion for painting the sea. It was a significant purchase, in addition to the crew’s wages that summer of £1,219, which was largely funded from the proceeds of his sale of Britannia’s Realm to the British nation (1880, Tate, Chantrey Bequest).

The Caskets Lighthouse is not, however, a record of his maiden voyage. Brett had passed within sight of the Casquets, Alderney nine years earlier, on 6 July 1874, when he took the GWR steamer from Weymouth to Guernsey for a painting campaign of four months; the present picture was reconstructed in Harley Street from sketches of that single July passage after receiving a commission from W. B. Rickman.

The sea is a magnificent turquoise underneath a summer’s sky of high cirrocumulus sky. Ships glide in the stillness of the water. The Casquets sit in the haze of the horizon, the lighthouse standing proud upon them. It in fact consisted of three stone towers built in 1724 by Thomas Le Cocq; at first coal-powered, in 1854 they were raised by thirty feet and converted to oil. In 1877, the Northwest Tower was raised again and fitted with a new first-order dioptric optic by Chance Brothers, one of the first group-flashing lenses ever made. The lights in the other two towers were extinguished and the towers themselves reduced. Brett’s picture accurately records them in their latest configuration, the diminished third tower just visible.

The exacting detail and luminosity of the painting belongs to the Pre-Raphaelite tradition, seen in Brett’s early works The Glacier of Rosenlaui (1856, Tate), admired by Rossetti and Holman Hunt at the end of that year, and The Stonebreaker (1857–58, Walker Art Gallery, Liverpool). Brett’s seascapes preserve the principle of ‘truth to nature’, and his ability to render waves and the play of light is testament to his exceptional technical ability. Its colour and serenity of mood is reminiscent of the artist's great seascape, Britannia's Realm of 1880 (Tate).

The painting was twice shown via the Whitechapel gallery in the schoolhouse of St Jude’s Church. These were not commercial exhibitions but charitable endeavours to benefit and educate the East End working class. The exhibitions drew thousands of visitors and regular lenders included Watts, Burne-Jones, Holman Hunt, Millais and Leighton.

The subject of the work also connects it to the poet and friend of the Pre-Raphaelites, Algernon Charles Swinburne, who wrote a romance called ‘Les Casquets’. It tells the story of a girl who lived on the barren rock and fell in love with a carpenter from Alderney but had to return to Casquets because she found life on Alderney too hectic. A label bearing four lines from the poem was at one time attached to the reverse of the painting: ‘From the depths that abide and the seas that environ / And rocks rear heads that the midnight masks / And the strokes of the sword of the storm are as iron / On the steel of the wave-worn Casquets’.

We are grateful to Charles Brett for his assistance and contributions to this essay.