Winston Churchill, British prime minister during the second world war and again in the 1950s, was firstly a politician and statesman, but secondly a painter. He was not an artist though. He described his paintings as “daubs”: they are the amateur output of a Sunday painter, more about mild stress relief than technically efficient vehicles intended for iconographic messages. There is an innocent charm in Churchill’s declaration that “the simplest objects have their beauty” – and in his encouraging others to paint too, without seeking fame or recognition. He exhibited modestly, and anonymously, in minor salons in the 1920s. Squinting (very) hard just about reveals the colourist efforts of perhaps a very minor impressionist-leaning painter, to be charitable, though any relation to the existing art historical canon is irrelevant: the works are of interest because of the identity of their creator, and as primary historical sources. They record where he was, when, and what he saw: variously stately mansions while staying with friends; bottles of his favourite tipples; Blenheim Palace and its grounds; holidaying in the French Riviera; and, inevitably, views while travelling as a statesman, such as Jerusalem in 1921, shortly after the Cairo Conference, which he chaired as colonial secretary under prime minister Lloyd George.

Curators Xavier Bray and Lucy Davis wisely avoid reading political views into these scenes, though can’t resist insinuating the odd symbolic link, such as between a cannon pointing out to sea in The Beach at Walmer (c 1938), a favourite bathing spot of the Churchill family, and his contemporaneous public warnings against Nazi Germany.

And yet. Assembled in such number – there are just under 60 paintings, acquired from around the UK and from private collections, a magnificent accomplishment – they have an overpowering joy, a charming amateurishness, made for pleasure and with no pretension. There is intrigue to be found in watching an amateur keenly learn, well in some areas (seascapes of the south of France demonstrate a love of bright, simplistic but dazzlingly contrasting colours, which the curators rightly deem his best work); but less so in others (let’s not talk about those figures and donkeys in his Marrakech scenes that would make LS Lowry blush).

Despite struggling to capture buildings with any degree of luminosity – it does take an actual impressionist to suffuse flat facades with life – there is a consistent vivacity stemming from the speed of application, evident in his Sketch of Lake Carezza, or The Twenty Minute Sketch (1949). Generally, he finds success less with painterly modelling – representational forms – than general surface “impressions” of light, water and sky using blobby dashes of colour.

It is unsurprising, then, to learn that he adopted both Walter Sickert’s techniques of establishing an initial monochrome layer underneath the colour, but also using a projector to transfer compositions, many of which came from photographs, on to squared up canvas. In other words, tracing.

The fact that many pieces originated from photographs also explains the bizarre sensation of scenes that feel adjacent to any kind of action, not least helped by the knowledge of Churchill’s actual political activities going on at the same time. The poor pictorial compositions give a strange skewed feeling of an uninhabited world, from 1916’s The View from Mrs Cassel’s House at Branksome Dene Near Poole, Dorset (with no strong focal point and vast spaces of, well, nothing), to The Italian Garden at Sutton Place (c 1930s). Though it’s improbable that adding people would help Churchill much.

This is a curio exhibition for people interested in “fine” art, and for those interested in the man as historical figure. You can see his eyeglasses (+2 strength in each lens), and beloved palette loaned from Blenheim Palace. But the exhibition itself was surely gestated before the attacks on Iran in February. Its actual opening has arrived during unprecedented global turmoil. That Churchill gifted his modest creations to US presidents, including Roosevelt, Truman and Eisenhower, or even took the time to soothe his temper with this gentle hobby, tells of a kind of genteel diplomacy and leadership that now feels totally archaic by comparison. In the current global climate, it is a hermetic cocoon of civility and passion for painting for its own sake.