The leading UK based think tank Open Europe has warned that a Norway-style relationship with the EU is "unlikely to be a viable long-term option" for the UK, saying this would be a "poor fit" when set against the Leave side's key arguments during the referendum campaign.
As the new UK government begins to formulate a Brexit plan, many businesses and some politicians have proposed the European Economic Area (EEA) model, or some variant of it.
This arrangement would leave the UK in a relationship with the EU that is similar to that of Norway and, crucially for the UK, keep it in the single market.
In its overview, the think tank says the EEA option comes with some notable benefits.
"It provides an 'off-the-shelf' model, thereby minimising short-term economic disruption and uncertainty, and could help smoothen some of the regional differences thrown up by the Brexit vote, such as those raised by Scottish First Minister Nicola Sturgeon."
EEA membership, it says, also means exiting some EU policies - such as those relating to agriculture and fisheries - and regaining the ability to negotiate stand-alone trade agreements with non-EU countries.
However, a Norway-style relationship is "unlikely" to be a viable long-term option for the UK, warns Open Europe.
It goes on, "Firstly, it is a poor fit when set against the Leave side's key arguments during the referendum campaign: restoring full control over UK immigration policy, restoring UK sovereignty over law-making including vis-à-vis the European Court of Justice, eliminating the UK's financial contribution to the EU, and reducing the burden of EU legislation on business."
It adds, "Secondly, and perhaps just as importantly, it is unlikely that such an EU-satellite status would satisfy the national self-image of a major G7 economy with deeper trade and foreign policy links across the world, such as the UK."
When it comes to thinking of alternatives to the EEA, the "realistic" choice, says the think tank, is between the EEA or some form of stand-alone comprehensive free trade agreement (FTA).
"One option," says the London-based Open Europe, "could be to seek reform of the EEA itself to account for the above concerns, but this would require the EU (and other EEA members) to agree to sweeping changes to a model that appears to have suited both parties relatively well to date.
"The FTA route is probably better suited to addressing the main political drivers of the Leave vote over the long-term, but it comes with its own set of problems, most notably the length of time it would take to negotiate - while the article 50 exit mechanism currently only allows for two years."
Open Europe states, "Moving straight to an FTA with the EU is also likely to cause more disruption to the UK's trade with the EU than the EEA option at a time when the UK is still establishing new trade agreements and seeking to deepen relationships with non-EU countries, which are crucial to enabling it to rebalance."
This leaves the possibility for a post-Brexit UK of a transitional EEA-style relationship, though Open Europe says it is unlikely that the UK would join the EEA formally, a more likely arrangement being one that mirrors the EEA in almost every aspect.
"However," it concludes, "even this would still come with many challenges."
These include controlling EU immigration, ensuring any EEA transition is truly transitional, managing the domestic politics, and making progress on the non-EU trade front.
"However, these challenges could be overcome if the UK and EU are able to establish the outline of a desired final settlement, even if the details will be subject to further negotiation. Indeed, a long-term vision for the UK outside the EU would be an essential component of any transitional phase."