This subject manages to be both vast and intimate at the same time. The light itself, coming from a veiled sun just out of the picture, seems to push apart the space we’re looking at so that it fills the long perspective of the open beach and glints on the distant water of the estuary with its flotilla of bobbing small craft. The proportions of the composition are expansive too: the width is twice the height, and emphasised by the horizontal-diagonal of the causeway that interrupts the bright recession with a quite unexpected dark band of shadow.

Wonnacott, who has painted this seaside place many times – it is his home – specialises in high blue skies scattered with clouds; here by contrast the sky is a misty white but the effect of scattering in the picture-space is achieved by the distribution of small figures: a brightly-lit stooping child at the left edge, another figure silhouetted against the water, a child running towards the right. Apart from these compositional pointers, there’s very little detail – not even the shells and stones we might expect on a beach; but we feel we are there, at the water’s edge, preoccupied with seaside activities under the all-enveloping sun.

This concentration on the dynamic potential of the space within the picture is typical of Wonnacott’s work. It’s the arrangement of objects or figures in relation to the geometry of the area they occupy that makes his subject matter. He loves the light-filled beach outside his studio window, looking out over the broad Thames estuary at Southend, and he has made it a recurring subject in his painting. He is linked to it as an artist in the way another East Anglian, John Constable, is linked to the Stour Valley on the Essex-Suffolk border.

The way he plays with space in his pictures recurs in many other works, including his ambitious portraits.

In the course of his career he has painted many distinguished people, as well as old friends (and himself numerous times). From the outset he has responded particularly to the challenge of the group portrait with its subtle playing-off of individual personalities against each other in terms both dramatic and spatial. The space itself is often a personality in the drama and he relishes splendid settings: a businessman in a huge crowded factory, the mirrored Victorian interior of the Tring Park school for the Performing Arts (with his son training as a dancer), the White Drawing room at 10 Downing Street for a portrait of Sir John Major, and another, even grander White Drawing Room for the Royal Family at Buckingham Palace. In each of these we see Wonnacott in different ways tackling the imposing spatial game of interlocking elements and dramatis personae.

He painted the Royal Family to mark the millennium in 2000, in a group including Queen Elizabeth the Queen Mother, her daughter the reigning Queen, Prince Philip, Prince Charles and his two sons still in their ’teens, not to mention four corgis. All these personalities interrelate with one another and with the spectacular interior in an unexpectedly informal way: a real family and not a mere photographic line-up. We can look back at Chalkwell Beach and see the same intimacy, the same dynamism there too: Wonnacott’s life’s work, varied as it is, is uniformly driven by his abiding sense of the inherent drama in all of life, the drama of individuals living out their existence on a multiplicity of levels profoundly and sensitively entered into.

All this can only be achieved by assured and masterly draughtsmanship. Unlike his better-known contemporaries in the so-called ‘School of London’, Wonnacott was trained at the Slade, where traditional skills were inculcated well into the twentieth century. His work is governed by perhaps old-fashioned disciplines, but in the hands of such an inventive artist these can only enhance the success of his ambitious visions.