A very large portrait painted on four joined panels. Lord Lewin is shown full-length, wearing the uniform of Admiral of the Fleet. He stands facing towards the right, looking upwards and out of the picture space. He wears epaulettes and has his right hand in his pocket and his left resting by his side. His legs are slightly apart, with the toe of his left foot just out of the picture space in the central foreground. He is positioned in the Painted Hall of the Old Royal Naval College at Greenwich (formerly the Royal Hospital for Seamen), standing in the Upper Hall close to the spot where Lord Nelson's body lay in state early in January 1806, with the Lower Hall behind under the dividing arch at its east end. The Upper Hall ceiling above him celebrates Queen Anne and Prince George of Denmark, her husband and Lord High Admiral. A decorative motif of shells and dolphins above, clearly visible, reflects the marine theme continued throughout the portrait, the blue of the floor and angle of the steps being emblematic of the sea. Behind the sitter, the angle of the windows, dining tables, and geometric pattern on the floor lead sharply towards the vanishing point at the main west door in the distance. The main ceiling of the Lower Hall, painted by Sir James Thornhill, 1707-12, is similarly shown to emphasize the effect of distance. Wonnacott further exploits and distorts Thornhill's use of perspective, illusions and allegorical allusions reflecting Britain's triumph as a maritime power.

The portrait was commissioned in 1995 to commemorate Lord Lewin's period as Chairman of the Trustees of the National Maritime Museum, 1987-95. It reflects on the Admiral's long and distinguished service in the Royal Navy from 1939, as well as his 50-year association with the College, whose buildings the Navy left in 1998.

The Painted Hall is famous for Thornhill's allegorical ceiling symbolizing the triumph of Peace and Liberty over Tyranny. Positioned in the centre, William III and Mary II are shown enthroned in heaven, surrounded by the Virtues. Below William, clutching a broken sword, is Louis XIV of France. This apotheosis of William and Mary celebrates two themes: first, the triumph of Protestant liberty over Roman Catholic absolutism - the latter expressly implied by the presence of Louis XIV and a fallen Papal tiara, and implicitly in the overthrow of Mary's father, the Catholic James II, in the 'Glorious Revolution' which put them jointly on his throne in 1688- 89; second, the subsequent prosperity and stability gained by Great Britain through sea-power and the Act of Union with Scotland of 1707. The ceiling is also full of allegorical mythological and historical figures celebrating British navigation. The stern of the man-of-war shown in the portrait is reputedly the 'Blenheim' and a reference to the Duke of Marlborough's victory at Blenheim in 1704 (though this was Sir Richard Steele's interpretation, Thornhill only referring to it as an unnamed British man-of-war). The figure of Victory features prominently, however, filling the ship with spoils and trophies taken from the enemy. Wonnacott is aware of the play of words between the allegorical Victory and Nelson's ship of the same name. The ship represents the Navy and implies patriotism and the power of the nation. Arts and sciences relating to navigation are represented by several motifs and emblematic figures, including named astronomers from an imagined one of Copernicus to a true likeness of John Flamsteed, the first Astronomer Royal at Greenwich. Other figures hold astronomical and navigational instruments and to the right the figure of Astronomy crowned with stars holds the armillary sphere of the heavens. Beneath the ship's stern a female figure representing London sits beside the male personification of the Thames, one of the four great rivers of England represented in this way in the overall design. Wonnacott has deliberately distorted the perspective in his concentration on the naval context of the painting. The ship's stern above the framing arch is in fact largely invisible from the viewpoint taken in the Upper Hall but the juxtaposition of naval allegory, distinguished naval commander, naval building and national identity is vital to the portrait. The use of the Upper Hall as the setting is also relevant, since Lewin and Nelson were both defenders of the realm.

Both artist and sitter understood the significance of historical connections and continuity, and the setting was arrived at based on many sketches. These included external options with the College buildings and Queen's House (this being part of the Museum) as background. The situation was complicated at the time by the British Conservative government's decision to close the Royal Naval College and treat it like any other defence property disposal: that is, asking estate agents to seek commercial bids for future use. This seems to have been a case of unthinking following of standard practise but for buildings of such major importance proved highly contentious, both in principle and as regards the likely options. In his personal capacity, Lord Lewin both deprecated the closure and had firm views on future uses. The Museum clearly recognized the important heritage issues involved but did not want the commissioned portrait of its Chairman to be read as a political statement (however unintended) on what was then a sensitive topic against its own government paymasters. At that time it saw a non-College background as more desirable but both artist and sitter favoured the setting finally adopted, the former commenting that 'after I had sketched him in many locations there could be no doubt that the Admiral should be shown standing in the Painted Hall in the Royal Naval College, just above the spot where Nelson had been laid after Trafalgar'. The portrait was allowed to grow taller to take in the whole of Thornhill's great ceiling allegory. In the event the Museum's misgivings were rendered groundless by the government decision that the College become a new headquarters campus for the University of Greenwich and Trinity College of Music. This course was already in train by the time the portrait was complete. Two changes which were incorporated were, first, the artist's wish that Lord Lewin be shown in uniform - something he rarely wore after retirement, usually stating 'I've left the Navy now'; second, at his request, that background figures which the artist had considered including in the Hall be omitted. The 'growth' of the painting in size is also evident in its structure. The portrait itself is in a single panel measuring 2510 x 1230 mm, to which two flanking panels of the same height, each 380 mm wide, have been added. A further landscape format panel, 1840 x 1990 mm, has been laid across the top of these to make up the full height and carry the image of most of Thornhill's ceiling.

Painted in a modern idiom, the work gains its effect from the relation of the figure to the picture space and the painter's intentional manipulation of perspective, which reflects Thornhill's of nearly two centuries earlier. Wonnacott also draws attention to the Baroque splendour of the Hall in the detailing of the ceiling, swags and torcheres. He places an emphasis on the use of gold and counterbalances the gold braid of the uniform with a vivid use of colour, particularly red and blue. This concentration on the elaborate may have been a response to a recent visit the artist had made to Venice. The monumentality draws attention to the stature of the individual depicted and the importance of the building. The painting is therefore an evocation of history, tradition, nationhood and a glorious Naval past as well as of the reflections of one man and his history, on a more personal level. One foot in the painting the other in our space as we move towards him, Lewin is shown in reflective mood and the portrait invites awareness of his own career as it marks the end of his long association with Greenwich, and on the end of Greenwich's 300-year direct association with the Navy.

Terence Lewin joined the Navy from a modest, grammar-school-educated background in 1939 and became a gunnery specialist. He spent a great deal of the Second World War in the Mediterranean, was mentioned in dispatches three times and awarded the Distinguished Service Cross for 'gallantry, skill and resolution . . . [when involved in] escorting an important convoy to North Russia in face of relentless attacks by enemy aircraft and submarines'. He went on to have one of the most a distinguished Royal Naval careers of the late-20th century. He became First Sea Lord in 1977 and as Chief of Defence Staff at the time of the Falklands War in 1982 played a key role in its success, being then the most senior serving officer whose experience included participation in the whole of WWII. He was a Trustee of the National Maritime Museum from 1981 and Chairman of Trustees, 1987-95. He was very pleased with the finished portrait, completed shortly before the onset of his final illness in autumn 1998.