Can the left exploit the state or must it transform it? This debate has recurred throughout progressive history. The Labourist tradition held that the British state – one of the most centralised in the Western world – could be used to impose “socialism from above”. Against this, others argued, as Neal Ascherson put it in his 1985 Mackintosh Memorial Lecture, that “it is not possible to build democratic socialism by using the institutions of the Ancient British state. Under that I include the present doctrine of sovereignty, Parliament, the electoral system, the civil service - the whole gaudy old heritage. It is not possible, in the way that it is not possible to induce a vulture to give milk.”

One of those who agrees is John McDonnell. At a Red Pepper event last night at St Pancras Church in London, the shadow chancellor declared that the left must be simultaneously “in and against the state”.

He explained: “The state is a set of institutions, it’s also a relationship, it’s a relationship of dominance, particularly a dominance of working class people about how they have to behave, how they can receive any forms of support or benefits from the state, the parameters in which they operate or even the parameters in which they think, to conform to the existing distribution of wealth and power within our society.”

One was reminded of Karl Marx assertion in The Civil War in France: “The working class cannot simply lay hold of the ready-made state machinery...The political instrument of their enslavement cannot serve as the political instrument of their emancipation.”

It was the task of elected politicians, McDonnell said, to “open the doors of that institution and transform the relationship from one of dominance into one of democratic engagement and participation. It’s that whole idea that you gain power to empower.”

To this end, McDonnell promised to abolish the House of Lords and replace it with an elected senate, revive local government, promote collective land ownership, establish democratically-run public utilities and ensure greater accountability of MPs (he is also, notably, a supporter of proportional representation).

McDonnell’s speech demonstrates how, as he has promised before, the next Labour manifesto will be “more radical than the last”. As well as a programme to transform the economy - with ideas such as universal basic income, a four-day week and worker ownership now under discussion - the party also has one to transform the state. Corbynism 2.0, as I have called it, is becoming clearer by the day.

He quipped of the Lords: “How can we have a society where 92 of the people that govern this country in the House of Lords are based upon who Charles I or II slept with?”

On land ownership – with 69 per cent of the UK’s 60 million acres owned by just 0.6 per cent of the population – McDonnell said: “One of the big issues we’re now talking about is land, how do we go about looking at collective ownership of land, Community Land Trusts, the development of those by local communities – that’s a huge challenge to the existing power relationships within our society at the moment, it’s one I think that could be fundamentally important. It’s the development of the ideas of ‘in and against the state’ at the local level.”

Labour has pledged to return the UK’s railways, energy, water and the Royal Mail to public ownership. But McDonnell vowed to avoid the top-down nationalisations of the Attlee era: “Bringing the privatised utilities back into public ownership but on the basis of them being democratically managed by workers, consumers and community representatives themselves.”

Recalling his past as the Greater London Council’s chair of finance, he noted: “One of the most effective things that made London Transport accountable was when we appointed Ernest Rodker, an anarchist, to the board of London Transport, he knew all the bus routes, what the fare schedules were and what ordinary people could afford, a new engagement and discussion and ideas about how you can develop transport policy based upon the real needs of working class communities. It’s no wonder that the first thing they [the Conservatives] did when they scrapped the GLC was to sack Ernest Rodker from the board.”

In past decades, McDonnell said, local government had been a crucial vehicle for the advancement of socialism. “That reached its height in the Eighties with the rate-capping campaign because Mrs Thatcher and the capitalist state woke up to the fact that this was happening, there was a transformation in the power relationships as a result of people being elected to work in local government.”

McDonnell also argued that Labour MPs could no longer simply be elected and told “off you go”. They must, he said, be held “accountable” – Labour has recently reformed its parliamentary selection rules to make deselections easier – and be supplemented by “new people as they come forward and the next generation that comes forward as well” (no more than 20 of Labour’s 257 MPs identify with the party’s left).

He added that, while celebrating the achievement of more than 500,000 Labour members, “we’ve got to convert ordinary members and supporters into real cadres who understand and analyse society and who are continually building the ideas”.

Oscar Wilde once quipped that the problem with socialism “is that it takes up too many spare evenings”. But McDonnell warned: “We can’t lose this opportunity by lack of commitment ... If we waste this opportunity, in 10 or 15 or 20 years, you will be kicking yourself, thinking ‘why did I miss that opportunity because I just wanted another night in.’”

His greatest fear, he said, was not the opposition Labour faces. “I don’t think there’s any force out there that can in any way undermine or defeat us.” Rather, “the biggest fear I have is our own lack of ambition and lack of mobilisation”.

He concluded: “Anything they throw against us we can overcome if we’re a mass movement which is aware of its own ideas, aware of its objectives and able to mobilise.

“That’s what we’re building but they’ve got to step up the pace of the construction of that movement, the building of that movement and the mobilisation of that movement. That’s my fear, I wake up in the night sometimes and think ‘my God, is there something undone that we should have done?’ And that’s where we’ve got to all have a responsibility.”