The British political marketplace increasingly represents a busy bazaar. It is chaotic and unpredictable. The old assumptions about fixed allegiances are crumbling. Customers shop around. They feel little obligation to be loyal. Their attention can be attracted by innovative new propositions.

To succeed in this furtive and fluid environment every political party needs to have a distinctive core proposition. The politicians who capture the public imagination have a clearly defined sales pitch. They stand for something unambiguous and argue for it with conviction. Their positions are black-and-white and their style is colourful. In this new era the absence of a unique selling point is a big problem. There is little public appetite for fifty shades of political grey.

The Liberal Democrats will struggle to command support in this marketplace without having a sharp definition. The appeal of cautious centrism is limited.

I call this ‘The Fresher’s Fair Test’: ‘Roll up, roll up, pay £10 here – help us dilute Ed Miliband’s ideas!’ How long is the queue at that stand?

If people want to protest they have protest parties. They have parties for Scottish Nationalism, British Nationalism and environmentalism. They have left-wing parties, right-wing parties. If they like Ed Miliband they can vote for his party; if they dislike him they can vote for a party that can defeat his.

Where is the demand for a tepid Milibandism or a watered-down Cameronism? Why buy the low calorie version when the full-flavour option is also in the marketplace?

But the big advantage the Liberal Democrats possess is that the party has the strongest claim to the greatest pitch in the marketplace – liberalism.

An unambiguous liberalism best captures the spirit of our era – freedom and opportunity. Free people, free speech, free markets, free thinking. It is egalitarian, internationalist and healthily subversive. A new generation – both economically and socially liberal – is looking for inspiration.

Liberals of all strands of opinion within the Liberal Democrats have exciting ideas that can capture the national mood. We need a standard that people can rally around.

A clearly-defined and self-confident authentic liberalism is that standard; moderating the ideas of others to make them marginally less bad is not.

Jeremy Browne is the Liberal Democrat MP for Taunton Deane

Tags: Jeremy Browne, Lib Dems, Nick Clegg, UKIP