Leading article: Mainstream politicians would do well to take heed

It has been quite a week in politics, beginning with a scandal over party funding and ending with an astonishing by-election result that should give all three main parties cause for concern. George Galloway's easy victory in Bradford West was most shocking for Labour, which should have had no problem holding the seat. In contrast, the Conservative treasurer caught on camera offering access to David Cameron in return for a large donation to the party coffers was deeply embarrassing for the Tories. Yet both events have implications for all three main parties.

Although Ed Miliband faces the most immediate questions, the by-election offers no comfort for either David Cameron or Nick Clegg. For Mr Cameron, who had aimed to break through in the north, it is a stark reminder of his lack of progress. For Mr Clegg, the result was little better. There was a time when Liberal Democrat opposition to the war in Iraq would have attracted a substantial protest vote in a seat like Bradford West. On Thursday, the party polled so badly it lost its deposit.

In fact, the outcome in Bradford West is part of a wider pattern as all three main parties struggle to adapt to changing times. Neither is it the only symptom of decline. Labour's dramatic fall from dominance in Scotland, and the SNP's concomitant rise, is another indication of public dissatisfaction with its usual options. So too are the Conservatives' failure to win an overall majority in the 2010 general election, the brief eruption of "Cleggmania" during the 2010 campaign, and now Mr Galloway's triumph. All suggest a bewildered, disillusioned electorate seeking inspiration beyond traditional party politics.

There is an important qualification with regards to the result in Bradford West. The constituency is an unusual one, often voting against national trends. Mr Galloway is also unusual, and chooses his battles carefully. He beat Labour's popular Oona King to her east London seat in 2005, for example, despite the fact that Labour won a landslide in the rest of the country.

Unusual or not, however, none of the three main parties can afford to ignore Mr Galloway's most recent success. There is simply too much evidence of distrust of politics in the rest of the country. Indeed, such disillusionment is hardly surprising, given the great insecurities created by the first economic crisis of the modern global economy. Although polls suggest voters blame the previous Labour government for the crisis, they have little faith in the Coalition to put it right. Neither has the past week's alarming amateurism from the Tory wing of the Coalition helped. From ridicule over Cornish pasties to an unnecessary panic over petrol, Mr Cameron and his party have only reinforced the sense that they are out of touch with the concerns of the majority.

Repeated scandals over party funding – of which the behaviour of Peter Cruddas is only the most recent – are part of the same malaise. Funding crises arise because falling membership levels leaves parties dependent on rich patrons or trade unions to survive. If they are to woo supporters back, they must do much more to adapt.

More than anything, the three main parties need to be bolder. In their timid search for the safety of the anodyne, politicians are becoming cautiously technocratic. And with worried voters seeing straight through the inauthentic banalities of the risk-averse party stalwart, there is space for a charismatic orator such as Mr Galloway, speaking with conviction, to sweep all before him.

The Bradford West by-election might have been a one-off, but mainstream politics has much to learn from it.