Labour’s 2017 general election manifesto is a big break with the recent past. Whether the manifesto allows the party to make a fresh connection with the British electorate won’t be clear until 9 June. What is beyond doubt is that this manifesto proclaims that politics and government in Britain do not have to be done in the way the country has long been accustomed to. That is true, and Labour is offering the country a real choice. So far, so very good, on both counts.

Jeremy Corbyn’s biggest achievement is to put several propositions back into the arena that had been thought extinct. That does not mean all of them deserve a new lease of life equally. Nationalisation in the shape of expensive, centralised public ownership is one to treat with caution, not least because of the power it gives to trade union leaders to drive up costs. There are signs that Labour’s economic team recognises that, but not enough detail about how it can be done. Other changes, though, are more straightforwardly welcome. The most important of these concerns taxation.

For 30 years or more, taking its cue from America, British politics took it as axiomatic that all voters will always recoil from increased taxes. Understandable though this was in some ways, it was a denial of the principle of social responsibility. As a result, throughout this era, parties have had to contrive ways of providing good levels of public provision without overt tax increases. Not surprisingly, this has become increasingly hard to maintain, and the effect on public goods has often been brutal. The no-tax assumption reached its nadir in 2015 when David Cameron and George Osborne promised no rises in income tax, VAT or national insurance for all. But it was an unachievable fantasy, as Philip Hammond found in the recent budget.

Labour is right to level with voters that tax rates cannot be set in stone for ever. Governments must be able to respond to economic changes, and those that want to invest in new programmes or projects must either borrow or tax to do so. Labour proposes to do both, which may alarm some voters. But the principle that fair and necessary taxes are a mark of a civilised society is the right one, and voters understand that they must rise as well as fall. Too few parties have been honest about this in recent times – the Liberal Democrats are an exception. Today it is not just Labour that is striding boldly into this territory. Even the Conservatives see the point of keeping options open. But it is Labour that confronts the issues with welcome audacity.

The real question is whether Labour is proposing the right level of tax take and the right mix of taxes and spending. There is a discussion to be had here. Taxes on income are very important, but taxes on wealth, including houses and land, which are less easy for the asset-rich to avoid, do not get as much focus as they should. Labour’s boldness does not extend to uprating and reforming council tax bands, for instance; instead only a review into reform is promised. There is nothing in the manifesto about fuel or alcohol taxes, both of which raise money and have social dimensions too. Abolishing tuition fees is an expensive subsidy to the better-off.

It is possible that the election has simply come too quickly for Labour to work everything out properly here. Some of the changes that have been made to the leaked draft last week add to that impression, though politics is involved too. The section on Trident and Nato has been sharpened at Mr Corbyn’s expense. The earlier plan to halt NHS reforms has wisely been replaced by a review. Looked at overall, Labour’s manifesto is a mixed bag of pledges, with some strange inclusions and other surprising omissions. Though radical in some ways it is conservative in others. The section on union rights is detailed and extensive, but that on the future of the United Kingdom is perfunctory. There is not as much sense of the future as there should be.

At 124 pages, this is a long manifesto. But it is not a suicide note. In terms of its social democratic credentials, the 1983 manifesto it most resembles is that of the Liberal/SDP Alliance rather than Labour’s. Its achievement is to expand the limits of the thinkable in British politics. Its weakness is that it does too little to make the thinkable seem realistic and practical. That reflects Mr Corbyn’s preference for energising his own support rather than persuading those outside it. This manifesto may not win Mr Corbyn the general election, but it could cement his support within his party.