When I first looked at what had been agreed on Brexit at Chequers, I thought the plan would please nobody, but that the public might conclude that these proposals represent the best available.

In reality, it’s a spatchcocked, half-in, half-out plan and the business response was frustration: it is better trade news for goods but a disappointing hard Brexit for services. Those who voted to “take back control” were more vitriolic: it is an attempt to remain close to Europe, full of concessions and compromises, and therefore a million miles from what they expected.

Theresa May: how much worse can the PM’s summer get? Read more

In Brussels on the day of the white paper’s publication, I met officials on the British and EU sides, as well as the Irish, and found a desire to debate its content seriously. For the last two years Theresa May has elevated sovereignty over trade and she seemed to be making a timely correction, as well as reaffirming her Irish border commitment.

But as I returned home, my earlier doubts resurfaced. This plan neither allows us to receive the economic benefits of being fully inside the EU’s trade perimeter nor will it give us the freedom to market ourselves independently to the rest of the world. It is a halfway house that will leave us hanging by a thread, subject to the EU’s rules – whatever they are in future – with no say in their formulation.

As a former EU trade commissioner, I know how complicated trade negotiations are and why they always end up with fewer gains on both sides than either expects.

So I am sympathetic to the government’s desire for something more ambitious and more customised to Britain’s needs. And I understand why the CBI has welcomed this ambition, particularly because it has chosen to prioritise international manufacturing businesses and their supply chains over services. However, it is services rather than manufacturing that make up the bulk of the UK economy and to relegate them makes no sense.

Furthermore, I am not convinced the government will hold to its plans for frictionless goods trade in the longer term. The product standards of goods traded will have to be the same as the EU’s – what’s called regulatory harmonisation – yet the government wants the right for Britain to determine its own rule book. So as to establish a single customs area with the EU, the government is proposing a “dual tariff” system – but this has never been tried before and relies on technology that does not exist to track goods. The structure is unlikely to survive an attempt to vary British tariffs so as to strike trade deals in other markets such as in America.

And while the EU will insist on a level playing field for rules governing competition, state aid and environmental and labour standards, the government has said that in future Britain must be free to “tear up” Europe’s “bureaucratic controls”.

Every aspect of the plan, is fraught with uncertainty about how it will operate in practice and whether it will endure. It will not be agreed on by the EU in its present form because of the issues of principle it raises for EU trade policy. If it is somehow accepted as a starting point for negotiation there is no chance of the detail being agreed by next March and its probable unworkability will only be exposed after Britain has left the EU, when Britain will have even less bargaining power than it has now.

At least if we were proposing to remain in the EU’s economic structures – the customs union and the single market – we would be anchored in a clear rules-based framework of rights as well as obligations and able to influence the terms of our association. The present plan offers Britain no such status. We would be subject to an arrangement never tried before, with thin legal recourse in which the EU would call all the shots.

It is the polar opposite of taking back control. Britain would be entrapped and the more you think through the implications the more the whole thing looks less like a soft Brexit than a national humiliation. Not only would it fail to secure all the trade we have presently but it would severely compromise our ability to negotiate future trade agreements with other countries.

You are drawn to the conclusion that it would be better to be fully in the economic structures of the EU or out of them altogether, and if you are in them, better to stay in the EU itself as this provides a seat at the table where the rules are made.

All this needs more time to work out. And, at the very least, a people’s vote so that the nation can determine its future – with a clearer choice for people than available in 2016 – rather than wait for the abject fate offered by the current plan.

Lord Mandelson is an ex-EU trade commissioner and business secretary