For Britain’s future prosperity, it is vital that close economic cooperation with our European partners is secured and sustained. Nearly half of the UK’s international trade is with the other EU member states, and our place in the EU single market is at the centre of the UK investment case. Departing from single-market regulations simply means more complexity for business, not more competitiveness; there is no evidence whatsoever that the agility of an independent trade policy trumps the benefits of scale in trade negotiations.

That’s why it is important for Britain to stay aligned with the single market and to form a new and comprehensive customs union. Brexit is a political departure but it does not need to be an economic rupture. The question is how these goals can be achieved while respecting the referendum result.

Compromise is inevitable. Labour’s shift in Brexit policy appears to reflect this understanding, and is a better approach than remaining in the European Economic Area (EEA), the approach known as the Norway option. Here’s why.

We proposed a new and comprehensive customs union, underpinned by a new UK court of justice and UK supervision authority

Advocates of Britain rejoining the EEA argue that time is running out, so we must take an “off-the-shelf” model. In the spirit of best is the enemy of good enough, is the EEA good enough for Britain? The short answer is no. Norway, Iceland and Liechtenstein must implement single-market regulations; and the four freedoms – goods, services, people and capital – apply just as they do to EU member states. The EEA states participate in committees to influence draft legislation, but they are not members of the single market’s decision-making structures. They have influence, but little leverage and no formal power.

EEA membership would mean Britain would have little option but to adopt regulations that it had no role in deciding. There would be no requirement to take into account British interests or objections. It would be democratically intolerable for a government to systematically implement decisions over which it had no say. And joining the EEA would substitute one European court for another. If Britain were to join, there would be a very real risk of a double-Brexit: leaving the EU and later crashing out of the EEA.

It would allow exploitative politicians on the populist right and left – and opportunist politicians in the centre – to continue to attribute Britain’s very real but self-authored problems to others and not to ourselves. The great deceit of British politics for the past 40 years has been passing off unpopular choices made in Westminster as instructions received from Brussels. EEA membership would allow that cowards’ game to continue, and resentment to build, nourishing a narrative of betrayal.

‘ A local labour market system could allows for priority to be given to job-seekers based in the UK in certain sectors.’ Photograph: Bloomberg/Getty Images

It is also a moot point. The EEA is not on the table in the Brexit negotiations because, while EEA members are bound to adopt single-market regulations, there are no consequences for failing to do so. For EU negotiators, this is a loophole so large that the world’s fifth largest economy could be driven through it. Moreover, they see it as a functioning agreement that they have no appetite to disrupt. The EU is not insisting on the EEA, so why promote an off-the-shelf model when a bespoke one could be negotiated?

The past two years should have been dedicated to building a new British partnership with the EU, a compromise that keeps us economically close while respecting the referendum result. Even now, Michel Barnier has said that the EU would be open to further negotiation during the transition, and indeed to a more comprehensive renegotiation, should there be either a change of prime minister or a change of government open to it.

As a new agreement, Britain would be able to negotiate a compromise on freedom of movement

It makes sense for the UK to seek a model that better reflects its priorities, in particular a clear and feasible option to diverge if future rules are introduced that run counter to our interests. Last December, we at IPPR proposed building what we call a “shared market”, based on regulatory alignment between the UK and the EU single market, and a new and comprehensive customs union, underpinned by a new, independent UK court of justice and UK supervision authority. The proposal has gathered interest from Brussels and other European capitals. It would solve the Irish border problem, too.

It would aim for Britain to stay in alignment but allow for the possibility of divergence over time, with a “declaration of incompatibility” that would give either side six months to bring regulation into alignment again. If they chose not to, then there would be proportionate consequences. Britain could choose to pursue a different path, not in the costless fantasy of the extreme Brexiters, but rather fully cognisant of the consequences.

Some aspects of single-market regulation could be more fixed than others. For example, workers’ rights and environmental protections could be subject to “non-regression” clauses that would protect British workers and assuage the concerns, particularly in Scandinavia, that the UK would undercut standards.

Allowing for the possibility of divergence would make it clear that Britain was making an active, positive and sovereign choice to be part of the single market. Moreover, it would give Britain a degree of leverage in how the European economic project develops. We would have traded power for influence with leverage.

As a new agreement, Britain would be able to negotiate a compromise on freedom of movement. This might include implementation of existing enforcement measures, restricting access to welfare payments as negotiated by David Cameron in 2016, and a Swiss-style local labour market system that allows for priority to be given to job-seekers based in the UK over European workers in certain sectors.

The shared market approach would honour the vote to leave, while reflecting the reality that the result was close.

Compromise is never fashionable. But the vast majority of UK people, whether they voted to leave or to remain, want the government to negotiate a deal that respects the referendum result without damaging the economy. In a shared market, there is the kind of compromise that might just work for both sides of the Brexit divide. If only the government were prepared to negotiate for it.

• Tom Kibasi is director of IPPR and co-author of The Shared Market: A New Proposal for a Future Partnership between the UK and the EU