The mantles of Nye and Mac

The voters of Blaenau Gwent and Bromley are feeling neglected. Both Blair and Cameron could be embarrassed by Thursday's byelections.

Voters go to the polls on Thursday to fill two seats in the House of Commons and one in the National Assembly for Wales. It is hard to imagine two places with less in common. One is an affluent south-east London suburb, the other a gritty working class south Wales valley. One had a Conservative vote of 51% in 2005, the other a Conservative vote of 2%. When Bromley sent Harold Macmillan to parliament as prime minister, Blaenau Gwent (then called Ebbw Vale) elected Nye Bevan with thumping majorities. But both may have similar messages for the political parties this week.

Bromley & Chislehurst is a mixture of suburbs, some of them extremely plush. Birds of paradise can be seen among the trees in Sundridge Park, and Chislehurst Common is genuinely high-class. However, Bromley itself is a fairly standard-issue suburban town, and Bickley are the sort of place that Delboy and Rodney would have ended up if they really did become millionaires. Bromley's Conservatism, like its late MP Eric Forth, tends to be of the brash, saloon bar variety rather than Cameron-style metropolitan gentility.

Perhaps the culture clash explains why the Conservative campaign in Bromley seems to have been accident-prone and unimpressive, a dinosaur compared to a lively and cheeky Liberal Democrat effort that has produced propaganda in the style of supermarket women's magazines and local tabloid papers. However, the Conservatives start with such a massive majority, and such a hard-core Tory electorate, that it is almost impossible to see them losing - although the majority will probably disappoint their hopes at the start of the campaign. Labour's strategic objectives in Bromley are to avoid coming fourth, behind Ukip's Nigel Farage, and to save their deposit - despite coming second with a relatively respectable 22.2% in 2005. The bad national climate, the usual poor government performance in by-elections and a developing squeeze from the Lib Dems all militate against Labour retaining many votes - although they should manage to get their deposit back and are probably likely to come just ahead of Ukip.

Blaenau Gwent is a very unorthodox election. After decades of voting solidly Labour (from 1929 to 1992 the MP was either Nye Bevan or Michael Foot) it went Independent in 2005. Peter Law, the sitting Welsh assembly member, stood against the official Labour candidate because of the use of an all-women shortlist and won. This is not the first such electoral tremor in south Wales - in 1970 Merthyr Tydfil overrode the local Labour party's deselection of its octogenarian MP, and in the first assembly election in 1999 even Islwyn fell to Plaid Cymru. On most occasions, Labour recovers quickly, largely because a vote for someone like Law is not seen as being "disloyal" to Labour. Ideas of community and Labour loyalty are deeply intertwined in Blaenau Gwent, but the loyalty is to an idea of Labour as movement and cause rather than necessarily what a Labour government does.

Candidates associated with Peter Law - his widow for the assembly vacancy and his agent for the Westminster seat - are standing in the by-elections. With Labour nationally at a low ebb, and a strong local socialist culture that tends to disapprove of the government from the left, what might have been an opportunity to proclaim a rare Labour gain seems to be fading. The better chance for Labour is probably the Westminster seat, although the UK government needs it less than the Welsh assembly government - which would remain a minority administration if Mrs Law holds the seat as an independent. The prospect of a non-Labour government in Cardiff after the May 2007 election would look that bit closer if the party loses out again in Blaenau Gwent.

These two constituencies, on the face of it Conservative and Labour heartland territory, show that in the right circumstances more or less any constituency is now capable of producing at least a warning, if not a shock result, for their natural party in a by-election. Perhaps it is disillusion and volatility. Perhaps, in this increasingly centrist, fuzzy new political world, the voices of the workers' social clubs of Blaenau Gwent and the saloon bars of Bromley alike are feeling a bit neglected.

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