“Is the novel dead?” comes the plaintive cry every few years, like the sound of Rachel weeping for her children. Sometimes it is novelists asking, interviewed by critics of novels before a paying audience of novel-readers, for the purpose of marketing their own novels, which will be reviewed by fellow novelists, and piled high in establishments dedicated to the sale of novels. The novel is not dead, of course; but if the concerned reader were to examine contemporary literature’s body of work they would find, in Amy Sackville’s virtuoso new book Painter to the King, nothing short of a vital sign.

Sackville’s 2010 debut The Still Point announced, within its fractured opening sentence, a writer assured of her ability to play with language and convention to startling effect. An account of a doomed Arctic endeavour framed within a single day, it begins:

Wait:

…

There. A little ellipsis, the smallest pause, opening for him to slide into. Then withdrawal and a full stop.

Praised by Francis Spufford as seeming “as if Virginia Woolf had had a younger sister”, it was followed in 2013 by Orkney, in which an academic frets, in elegant, allusive prose, that he is losing his young wife to the eerie lure of the Orcadian shore. In the light of these it would be inaccurate to say that Sackville, in Painter to the King, achieves her promise – from the first, what she offered was not promise, but fulfilment – but her third novel is certainly the most muscular and confident expression yet of her extraordinary gifts.

The painter is Diego Velázquez; the king, Philip IV of Spain, who in 1622 issued a command to Velázquez that he must leave his native Seville for the royal court in Madrid. The novel begins with the narrator (who may be, though one cannot say for sure, Sackville herself) in a gallery, imagining herself shoulder-to-shoulder with the artist, assessing and acquiring his gaze:

I was –– but also at the same time you – I was there and also watching and you – and then –– But – then again –– step closer, and it’s all just a surface of smears…

There is nothing self-conscious or alienating about this style, interspersed with hyphens, sometimes two at once, repeating and contradicting itself: it is a clever evocation of a mode of thought in which imagination and reality cohabit. There follows an account of the painter’s journey to the city, seen with the acuity of an artist’s eye. The sight of eggs cooked in a cracked dish is immediately transmuted into a potential painting: “so if his brush-line were to follow its form he would include in the foreshortened oval that bentness, that dent” (a reference to Velázquez’s remarkably vivid work An Old Woman Cooking Eggs).

In Madrid, the painter bears witness to the machinations of a decadent royal lineage entombed by its own excess. The young king is desperate for an heir to secure the line; the queen produces daughters, or sickly boys, or nothing at all. He dines in majestic solitude “attended only by his prelate, his major-domo at his side, and a carver, a butler, a cellarman, and the royal physician, on hand to approve all that is served to him; some mace-bearers, footmen; only the most necessary staff”. His closest adviser, the Count-Duke, brings papers for the royal signature, surveys his sovereign with anxious affection, grows old; the red-haired singer and courtesan La Calderone is more or less immured so that her body is preserved only for the king’s use. Cardinals, secretaries and visiting royalty attend the court; princes are sent to battle; the borders of Spain are never safe. Summer palaces are built, extended and extended again; poets gossip, and leave spiteful notes for the Count-Duke.

The king ages. He mourns lost children, and in due course a lost wife; he grows fond of Velázquez, who records, in canvas after canvas, the procession of men and women in and out of court like gilded characters that appear hourly at the strike of a mechanical clock. The painter is a rare fixed point and the king favours him; sometimes he stands mutely in the studio and watches his own face appear on the canvas. A number of Velázquez’s works are described, but never with merely an observer’s view, since Sackville has a genius for evoking the painter’s questing, dissatisfied mind:

He works and reworks over it … dip, swipe, dip, swipe: The leg of the horse curves up into the belly here, like –– Here, the top of the leg rounding into the socket like –– The curve of the belly barrel-like –

–– No

Occasionally details of paintings are reproduced on the page – a gloved hand holding a letter, a single eye. Sackville’s research has evidently been exhaustive, but the effect is not that of reading a primer on a long-dead subject; the novel embodies Pound’s modernist maxim that one must “make it new”.

Throughout, the reader is accorded glimpses of the narrator, a melancholy meditative presence walking the streets of contemporary Madrid and Seville, feet blistered by ill-fitting sandals, surveying empty spaces where Velázquez had been and finding him still there. In this respect, the novel calls WG Sebald to mind, if he’d struck out for Spain, and not East Anglia: the author is concerned not only with her subject, but with her relation to it. “Oh, poor painter – I am with him, I have been here.”

The novel is not propulsive in the ordinary sense. Rather, it is entirely immersive, as if the reader comes slowly to realise that they have been inhabiting a Velázquez canvas all along. What especially thrills is Sackville’s style, which revels in risk and play. It is now so hoary an adage that good prose is “clean” or “taut” or “spare” – as if it were a sheet on a hospital bed, not the work of an artist – that to encounter a page richly stitched with image and metaphor feels almost transgressive. Not only does Sackville deploy adverbs whenever she chooses, she coins them: a river “gurgles brownly by”, the soil is “stubbornly, unabsorbently dry”. She is especially alert to language as sound as much as symbol, and often phrases ring like melodies: a poet’s bald head is “a crucible for the cultivation of verbal curlicues”, and he competes to see “who can stretch an absurd verb the wordiest”. The effect is leavened by a Mantel-like willingness to make the historical immediate by the use of contemporary turns of phrase (“So, we’re back, Diego. And you have other things to do”).

Novels about art and artistry are plentiful; many are very good. But in Painter to the King Sackville has written not only by far the finest novel of its kind that I have ever read, but one of the finest historical novels of recent years. For her skill and daring, her assured grasp of both subject and form, and her masterly chiaroscuro of human failure and endeavour, she is as distinct among her peers as Velázquez was among his.

• Sarah Perry’s novel Melmoth is out in October from Serpent’s Tail. Painter to the King is published by Granta. To order a copy for £12.74 (RRP £14.99) go to guardianbookshop.com or call 0330 333 6846. Free UK p&p over £10, online orders only. Phone orders min p&p of £1.99.