English Conservatism needs a makeover. It is vital for our integrity as a country that it should fast rethink its relationship with Britain and the British – otherwise, there won’t be a Britain.

Detached from Scotland, the England over which it aims to preside, never-endingly, will be a poisonous, inward-looking and mean-spirited place. It will be welcome only to the super-rich and their insider networks, denying the mass of English citizens the structures and institutions through which they can live the good lives to which they aspire.

The Britain I love – an outward-looking country that is tolerant, good-humoured, fair-minded and generous, and which, with some reforms, could become one of the most dynamic places to live in Europe – will have been expunged.

Political parties in great democracies have a double function. They must represent their philosophy and coalition of supporting interest groups, but they must also speak for the whole. Of course a centre-right party will favour less tax and state, be pro-business and be wary of working-class institutions. Equally, a centre-left party will represent social justice, equity, redistribution and ordinary workers. These are their twin roles. It is from their “turns” in government that, over time, a country builds its institutions and laws. Both are vital elements in the polity, learning from the other; and at different times, it falls to one to govern – but to do so in the interests of all. Britain owes its National Health Service to one tradition; its flexible labour market to the other.

The tragedy of British politics is that today our centre-right has gone rogue. The English Conservative party, which always had a tendency to be as fierce a partisan for its class as any party of the extreme left, has so deified its self-appointed role as custodian of Englishness that it has given itself permission to put its own interests before those of the country.

One of the most revealing recent political moments was David Cameron’s statement outside Downing Street the morning after the Scottish referendum. It was a moment for a big speech of generosity and national reconciliation – to heal divisive wounds and, above all, to try to rebuild the sense that Britain is one country with a shared destiny. But Cameron could not place the interests of country above party. Instead, he shamelessly pandered to the English nationalists in his own ranks and their panic over the challenge from Ukip, insisting on English votes for English laws as the quid pro quo for any settlement with Scotland. If Scotland ever secedes from the union – bad for both countries – Cameron’s speech will be seen as the decisive moment of fracture.

Tribal partisanship and a readiness to trash great institutions to serve the party interest suffuse the Conservative position. British justice is one of the jewels in our national crown. The refusal to raise taxes and place virtually the entire burden of deficit reduction on incredible cuts in departmental spending, with more ahead if Osborne’s plans are to be believed, has had many casualties. But one of the least discussed is the impact on the criminal justice system.

Legal aid, probation, policing, the prisons, the courts, the Serious Fraud Office and the Crown Prosecution Service are all reeling from cumulative budget cuts averaging roughly 30%. Yet any society worth its salt should surely enshrine the capacity to deliver justice to all its citizens, however poor or disadvantaged, along with a commitment to rehabilitate those who have served their time. The institutions that provide them are not residuals, receiving whatever crumbs are left before the higher aims of never raising taxes and balancing the budget are achieved. They should be central to our civilisation.

So should the willingness to make common cause with other like-minded countries to uphold basic principles of human rights. Yet the Tories are determined to withdraw from the European convention on human rights in which all citizens are protected from torture, arbitrary detention, snooping, censorship and discrimination. Parliament should be sovereign, runs the argument, rather than some “European” court: what that means in practice is that transient majority parties in the Commons will be the final arbiters of justice. If the party decides someone should be flung out of the country, snooped on or detained without trial, then it should be free to do so.

The list goes on. The Conservative controlled state is, arbitrarily, to confiscate the assets of private social housing associations to sell them off cheaply to tenants, for no better reason than to create more Tory voters. The BBC’s licence fee will be frozen and its non-payment decriminalised, ensuring that another great British institution that dares to try to represent the whole will be sacrificed to ensure Tory hegemony. Further education, a lifeline for millions of adults struggling to make something of their lives, will be emasculated further still. Millions more on low wages dependent on the top-ups, tax credits and help for children that makes family life just about sustainable will be at the receiving end of yet more cuts: there is no other way to achieve the famed £12bn of welfare reductions.

Nor will there be any attempt to reform the core institutions of British capitalism – the firm, the shareholder or the City – to make them more productive. All can continue as before. Meanwhile, we are to believe that billions more can be spent on health, taxes frozen and the national books balanced. Inequality, the defining feature of our times, will be unchallenged.

Then there is the EU – a key relationship so much more important than trade and jobs. Conservative advocacy of membership is impossible. We cannot even act with France and Germany to try to protect Ukraine from Mr Putin. All that matters is to ensure that England is run by Tories in the Tory interest.

Mr Miliband and the Labour party have been subject to outlandish vilification. Yet it is they who are trying to save both the union and our relationship with the EU, and they who seek to conserve our great national institutions, address the worst social inequalities and, paradoxically, develop a more vigorous capitalism. So do the Lib Dems. I know many good Tories in quiet despair at what their party has become.

Whatever happens next week, Conservatism should not be allowed to escape from what would have been the people’s verdict. Britain already has Ukip. British democracy does not need two rogue parties of the right.