As more 'harbingers of reconfiguration' emerge, far from solidifying into distinct blocs, the geopolitics of the UK may become even more complex yet.

The Dulwich Picture Gallery is currently showing an exhibition of the work of the English painter, printmaker and designer, Eric Ravilious. Ravilious, who died on service as a war artist in 1942, is perhaps best known for his work as a designer and illustrator, but he also excelled at painting watercolours, principally of southern English landscapes, and these form the basis of the exhibition. He painted in the restrained palette and nostalgic idioms of a peculiarly English modernism, eschewing the dominant 1930s schools of abstraction and surrealism in favour of a more conservative, romantic pastoralism. In his hands, rural England achieves a harmony and luminosity that is aesthetically satisfying, but never sentimental. His art is recognisably of the 20th century, but never avant-garde.

In this sense, Ravilious's work, like that of his friends and contemporaries Edward Bawden and John Piper, reminds us of how Englishness has historically been crisscrossed and defined by both conservative and radical traditions, putting in play creative tensions that have shaped the popular culture and politics of the country. (The art historian Alexandra Harris called her study of 1930s English art Romantic Moderns, which captures this well.) In turn these have generated a diversity of expression which belies the derogatory associations of the term 'little England'. Englishness is rich and pluralist, shot through with differences of cultural identity and political allegiance that defy simple categorisation on north/south or left/right axes.

That is why Paul Mason's characteristically suggestive division of the UK into three geopolitical blocs – 'Scandi-Scotland', an asset-rich South East, and post-industrial rUK – is flawed: it homogenises the politics, economics and popular culture of each out of recognition. Scotland has social democratic political institutions, but public opinion is not markedly different on most issues to that found south of the border. It has become politically distinct in recent years by virtue of the decline of its unionist parties in the face of a resurgent civic nationalism, the waning of older, pan-British class loyalties, and a shift away from Labour among its Catholic core vote, not because Scotland has evolved a Nordic political constellation.

Similarly, the economy of the south-east of England may be critically dependant on the global flows of capital coming into the City of London, but it is not a homogenous conservative political bloc, undergirded by a culture based on the accumulation of asset wealth. It is sharply divided by social class, from South Thanet to the Thames Valley, but also politically heterogeneous. Labour is strong and getting stronger in London, where a disproportionate share of its activists now live, but still weak in the towns of Essex and Kent that it swept up in its 1997 landslide. Brighton is a Green heartland, every bit as dependent on London's wealth as Guildford but resolutely ecoconscious and socially liberal in ways that are unimaginable in the deep blue heartlands of Surrey.

Further west, you encounter an older, liberal England in the towns and counties of Dorset, Devon and Cornwall, where the Liberal Democrats are fighting to stay alive. They share a non-conformist heritage with Lancashire, but none of the popular culture of Mason's Blackpool and Preston clubs and workplaces. Throwing a post-industrial blanket over these different parts of England makes little sense. The Green party is strong in Bristol, a city at the leading edge of the innovative post-industrial economy, but makes little political headway outside this urban core; in this part of the world the laylines of environmental consciousness and social solidarity run towards Labour pockets in Exeter and Plymouth, and left-leaning Lib-Dems along the coast. Eventually, they reach land's end in Cornwall's distinctive politics, where ancient identities still scrape the surface of mainstream politics and Mebyon Kernow keep alive the ambitions of the Cornish centre-left.

Indeed, Mebyon Kernow is one of the better known of a range of regionally based parties that are starting to emerge as the vehicles for English decentralist demands. Less vocal than the new English national party groupings calling for an English parliament, these parties are nonetheless becoming more numerous and visible: Yorkshire First, the North East party, and the Campaign for the North among them. They are explicitly democratic in their goals, seeking to share in Scotland's civic renewal and to wrest back powers from Westminster. Although they will lose their deposits on 7 May, they are harbingers of a reconfiguration of English politics, one that is likely to spread decentralisation and its accompanying political energy out from the dynamic city-regions to their neighbouring towns and counties.

We lack a contemporary Rural Rides to document this shifting Englishness; our best substitutes are to be found in the reportage of James Meek or John Harris and the acerbic architectural criticism of Owen Hatherley. But political scientists such as Arianna Giovannini are starting to research and document this new regional English politics, building on the studies of English political nationhood pioneered by Mike Kenny and others. Moreover, if the SNP holds the balance of power in the next parliament, we may find that surprising new alliances for federalism and decentralisation emerge in the UK. Wales too – where Labour remains strong, and a large Ukip vote belies its reputation as an English national party – may begin to exercise greater leverage over constitutional debates. Far from solidifying into distinct blocs, therefore, the geopolitics of the UK may become even more complex yet.