Last month the Westminster government set out its blueprint for policing trade between different parts of the UK after the post-brexit transition period ends on 31 December. Under these proposals, Scotland, Wales and Northern Ireland will be given additional powers over areas including air quality and animal welfare which are currently regulated at EU level.

There is, however, an important quid pro quo within the blueprint, designed to safeguard cross-border trade, in which the home nations will be required to recognise standards drawn up elsewhere in the UK.

Despite the claims of the UK government that its proposal will enable ‘the biggest transfer of powers in the history of devolution,’ the governments of devolved administrations are not so convinced. In Scotland, the SNP claim the plan would actually ‘strip power’ from the Scottish Parliament.

With legislation for this proposal scheduled to follow later in the year, it would be wrong to view this brewing disagreement as a technical debate reserved for government officials and political boffins. These new rules are likely to have an important impact on everyday life.

Throughout the UK there are serious concerns about whether post-brexit trade deals will lead to the acceptance of lower standard products from abroad. Equally, there are issues about the security of cross-border trade between the four home nations, which will have a direct impact on many of our indigenous businesses.

Given the amount of detail currently missing from the blueprint, which appears to be an attempt to mirror the EU Single Market within the UK, I would share the Scottish government’s concerns about its potential impact on the devolution settlement. This also raises further concerns over the profound effect it could have on the separate nature of Scots law. The proposal’s aim of creating a system of ‘mutual recognition’ appears to replicate the minimum standards that underpins the freedom of movement of goodsinthesinglemarketbutthere are major differences.

In the EU system, no member state is powerful enough to dictate standards and there is a complex oversight system involving the EU Commission, Council of Ministers, national governments, and the European Parliament to create broad consensus. The same cannot be said of the UK system, due to the disproportionate strength of the English market and likely unwillingness of the Westminster government to agree to a consensual system involving the devolved administrations. Practically, this could potentially result in lower standards, agreed by Westminster to secure global trade deals, being forced on devolved nations.

The often-quoted ‘chlorinated chicken’ that commentators have raised as the price of a US trade deal could be replicated in agreements with other nations. If such standards were forced upon Scotland, it would potentially cause reputational damage on our high quality and economically vital food and drink export sector.

Westminster hegemony over these matters would also adversely impact aspects of Scots law which, rather than remaining innovative and reflecting Scottish concerns, would merely become a rubber stamp of English law. There are concrete examples which highlight this concern, such as the role of Scots law on minimum pricing of alcohol, which the US government has already identified as a potential barrier to a future trade deal with the UK. There is a real threat to this and other areas determined by Scottish law that would be overridden by the UK government to secure such an agreement.

These concerns about the internal market proposal could be mitigated through adequate input from Scotland, just as we have seen Quebec inputting on Canadian deals or the Flemish consenting to the Belgian government progressing with EU trade deals. Unfortunately the mood music currently emanating from Downing Street is that Holyrood will have no meaningful role.

Indeed, there are fears the UK government or one of its agencies will have the right to challenge and invalidate Scots legislation, a development that until now had been restricted to the UK Supreme Court on normally very limited human rights grounds.

Making aspects of Scots law irrelevant would represent a major reversal of devolution and create a major constitutional crisis which threatens Scotland’s long term future in the Union.

Stephen Phillips is a partner and member of the Brexit Group at law firm CMS.