Thomas Lawrence, National Portrait Gallery

    Thomas Lawrence — high-society lackey or giant of portraiture? The National Portrait Gallery is too refined an institution to ask the question that bluntly, so its Lawrence exhibition is presented instead as a thoughtful attempt to return a neglected Regency star to his rightful place in the firmament. Fair enough. But if Lawrence is not being given the credit he deserves, then the reasons for this neglect are clear: the modern world has him down as a lackey. The National Portrait Gallery’s task is to prove us wrong.

    The gallery began its defence badly in August with an ill-judged press launch that attempted to pass Lawrence off as a fascinating Regency sex pest. This nakedly manipulative press effort zoomed in on his simultaneous love affair with two of the daughters of the much tortured Sarah Siddons, the greatest tragic actress of the times, whom Reynolds immortalised in one of his mightiest portraits. The news that Lawrence had jumped out of one Siddons bed into another, and that Mother Siddons had screamed in despair at “this wretched madman’s frenzy”, may, indeed, have brought Lawrence some modern attention. But it did nothing to nuance his reputation.

    What a relief, therefore, to find the exhibition itself not only avoiding entirely the topic of his tortuous testosterone, but also proving, beyond any conceivable doubt, that he was indeed a much more substantial and talented artist than most of us had suspected. To make his achievements extra-impressive, it seems Lawrence was largely self-taught and popped out of his mother’s womb, in 1769, already talented. His father, a humble innkeeper from Bristol, remembers little Tommy reciting Milton to the pub-goers by the age of six.

    Even allowing for the usual exaggerations that are passed on about prodigies, it is clear that this boy was preternaturally gifted. In fact, on this evidence, we could probably conclude that he may have been the most naturally gifted painter these shores have produced. Not even Turner was as fluent at 18 as Lawrence is in the first self-portrait we encounter here. Yes, the characterisation is wide-eyed and sweet. But, my God, look at the fast paintwork.

    As always with prodigies, the career ahead becomes a battle between true achievement and an easy life. In most comparable cases, the easy life wins. For every Picasso, there are scores of Augustus Johns. Lawrence, to his profound credit, was never satisfied. And because he was so quick and fluent, trying new things didn’t scare him. The NPG does not unveil a Regency Picasso — he wasn’t that good — but it does give us an artist who never betrayed his gifts.

    The young Lawrence so impressed the elderly Sir Joshua Reynolds, president of the Royal Academy, that he was fast-tracked into its ranks in 1791, the year before Reynolds died. And the show’s first spectacular helping of his portraits, painted when Lawrence was 20 or so, reveals immediately what he possessed and what Reynolds spotted in him. To be fair, it’s unmissable.

    A young actress, a tall, pale slip of a girl with gorgeously impish eyes called Elizabeth Farren, turns those delectable eyes on us with an assassin’s precision as she glides across a huge English landscape in a white satin gown edged with sable. Ravishing. Next to her, the reigning British queen, Queen Charlotte, unfortunate wife of the mad George III, sits in a room that seems too big for her. Her Majesty has something of the caged bird about her: how small and trapped she looks. Grey hair, white dress: she’s an imprisoned snow queen from a fairy tale, and for an artist of 20 to see this much fragility and nervousness in his monarch, and then to have the nerve to paint it, is exceptional.

    So Lawrence could do women. But the mark of a truly significant portraitist is not their facility with female beauties — where nature has already done much of the work — but how they cope with ugly old men. That is a challenge. To which Lawrence rises impressively throughout the show.

    Richard Payne Knight, a red-cheeked Timothy Spall lookalike granted no obvious physical gifts by nature, was smart enough to become one of his era’s finest connoisseurs. So Lawrence has him looking out over our shoulder at the cosmos, thinking so hard about distant aesthetic mysteries that he doesn’t notice us.

    We, in turn, barely notice the unfortunate absence of his chin. At the other end of the show, William Wilberforce, the history-changing anti-slavery campaigner, granted Lawrence only one short sitting. The painter barely had time to finish a sketchy head. But how supremely well he catches the “winning sweetness” of the great do-gooder.

    Much is made in the exhibition paraphernalia of the turbulent times Lawrence had to live through and the impact they had on him. The year after he was accepted by the academy, the French revolution exploded. Its consequences were to vibrate all the way through his career, to his unexpected death in 1830. In 1815, when the war against the French was finally won, he was sent off on an official state tour of Britain’s allies and spent five years making himself internationally famous by painting Europe’s greatest statesmen, generals, popes, archdukes and their mistresses. As a result, his work slipped quietly into their castles, parliaments and locked-up palaces, and out of our easy view.

    In the show’s most spectacular loan, the Queen has lent three huge full-lengths of Britain’s wartime allies from the Waterloo Chamber at Windsor Castle: a beefy Field Marshal Blücher; a giraffish Archduke Charles; and the dormousey Pius VII. In a field of grand state portraiture in which genuine lackeys always watch their back, Lawrence continues to paint with reckless courage and finds so much humanity and character and weakness in his all-powerful sitters.

    The finest of the three, the curled-up Roman pope, is a spry old man sinking impishly into St Peter’s huge throne like Tom Thumb sitting on Cyril Smith’s chair. It’s as fine a papal portrait as anyone has ever dared paint. What a shame Lawrence was never unleashed on Napoleon. However, we do at least have the most tangible, least mythic, of Wellingtons. So, he could do generals, women, old men, queens and popes. Any fabric you placed before him — fur, silk, velvet or densely embroidered satin — he evoked with contemptuous ease. Even his background landscapes are convincingly brooding and big. His one glaring weakness was his children, who are always too wide-eyed, too rosy, too sweet. Since we can count the truly great painters of children on two fingers — Picasso and Velazquez — it’s a fault that is easily forgiven.

    The show set out to convince us that we were wrong to forget Lawrence and that he deserves to be seen as one of Britain’s finest painters. Job done. If this gripping display fails to put Lawrence back on the European art map, then the map needs replacing.