Picasso and Modern British Art, Tate Britain, London Mondrian//Nicholson: In Parallel, Courtauld Gallery, London

That Ben Nicholson is the co-subject of two major exhibitions in London this month suggests something is afoot.

True, he has been shown in further-flung galleries in recent years – at Tate St Ives, and, with Alfred Wallis, at Compton Verney. But Nicholson's last major outing at the Tate was in 1993, which tells you all you need to know about his place in English fashion. Now his work is being shown not only at Tate Britain but at the Courtauld Gallery, and alongside that of two of the greatest names in European Modernism: respectively, Pablo Picasso and Piet Mondrian.

It is an interesting moment. For many years, the masters of what is broadly called Modern British have been filed away in a box marked "fusty". The generation that came after them – the hotheads and young Turks of Op and Pop – looked outwards, to America, Arte Povera, to Situationism. They also looked back, and didn't like what they saw. What they saw was a generation of British artists who had bottled out (if, indeed, they had ever bottled in), turning their backs on international modernism to paint Windsor Castle under dark skies and fishing boats at Mousehole. Nicholson and the rest were Little Englanders, late Victorians, old farts.

As often with the judgements of the young, this was unfair. British artists had engaged with Europe from 1919 to 1939 in a way that the generation that followed them could hardly dream of. Picasso had been a particular source of fascination and despair. John Piper's wife, Myfanwy Evans, recalled Picasso as "the Protean rock which slipped from our fingers when we clung to it, upon which we foundered when we pretended it was not there; whose personality and aggression acted upon us like rape". That "rape" – mostly consensual – is the subject of Picasso and Modern British Art at Tate Britain.

The first thing that strikes you is the size of the show. Broader in remit than the Courtauld's Mondrian equivalent – the last rooms are of David Hockney's responses to Picasso, made after his hero was dead – it is honest in owning up to the mixed reception its subject had in this country. The first Picasso entered a private collection in London as early as 1911, but was bought by a resident Dutchman called Stoop. Hugh Willoughby, impeccably English, bought several, but while living in Paris and late on. The first painting in a British public collection – the Tate's – wasn't acquired until 1933, and even then was Picasso's Flowers, done, pre-Cubism, in 1901. It is not an entirely happy tale.

All this suggests the appalling conservatism that Nicholson and his kind were working against. It took a strong man to toe the Picassoist line, and these were few. Wyndham Lewis, initially seduced by Analytic Cubism – thus paintings such as his Vorticist Workshop – was soon dismissing Picasso as "cultivated and snobbish". The most direct beneficiary of the Spaniard's genius was Henry Moore, but Moore's softened-up sculptures have nothing of the rigour of Picasso's. The central part of the Tate's show, covering the 1920s and 1930s, is to a large extent about failure: the impossibility of grafting something hard and empirical on to a national tradition that reverts, inevitably, to lyricism.

Over at the Courtauld, the story is more focused and more tragic. The last Picassoesque Ben Nicholson in the Tate's show is Saint-Remy, Provence, a double portrait of the artist and his wife-to-be, Barbara Hepworth, painted in 1933. The following year, Nicholson met an artist whose extreme position made Picasso's seem fluffy.

I wrote last week about Nicholson's alliance with Piet Mondrian, so will omit the broader story of this show: the title, Mondrian // Nicholson: In Parallel in any case spells it out. This small, clever exhibition looks at the rare moment when an English artist nearly became a modern one. The Courtauld has borrowed Mondrians that Nicholson is likely to have seen, and suggested his response. Works such as 1934 (painting) show the immediacy of his reaction to Mondrian's Composition A and the like, and its difficulty. The work struggles to escape Cubism, representation, and from being seen to be Mondrian-ish.

It is in Nicholson's White Reliefs that he finally finds a voice all his own, Mondrian-like only in being pure and modern. Within five years, the war had come, Nicholson had left London for Cornwall, and abstract art was declared un-British. The experiment was over. Here, on the Courtauld's walls, is a brief moment of hope, all the more poignant for our knowing it was dashed.

'Picasso and Modern British Art': Tate Britain, London (020-7887 8888) to 15 Jul; 'Mondrian//Nicholson : In Parallel': Courtauld Gallery, London (020-7872 0220) to 20 May

Next Week:

Charles Darwent joins the masses at the Hayward's Jeremy Deller: Joy in People

Art Choice

Tate Modern has gone dotty with a major retrospective of the work of Japanese artist Yayoi Kusama whose paintings, collages, sculptures and installations share an obsession with repetition, pattern and accumulation (to 5 Jun).