Britain could strike post-Brexit free trade deals without the approval of the Scottish and Welsh governments under proposals circulated by international trade secretary Liam Fox.

Dr Fox has written to Cabinet colleagues setting out four options for devolved governments' role in negotiating free trade agreements after the UK leaves the European Union, a Whitehall source confirmed.

One of them includes making trade a reserved matter for the UK Government, although at the other end of the spectrum is a proposal that a common position should be agreed with devolved governments before striking a deal.

Any move to freeze out devolved governments is likely to be strongly opposed in Edinburgh and Cardiff.

The government has not taken a decision on which option it prefers.

However The Times claimed Dr Fox favours denying Scotland and Wales a veto, and Tories worried about the anti-Brexit SNP scuppering any free trade deals could back him.

Genetically modified (GM) foods - which are legal for cultivation in England and the US but banned in Scotland, Wales and Northern Ireland - are one potential flashpoint in trade talks.

The UK Government is set to publish a trade white paper in Autumn, ahead of a Trade Bill.

A department for international trade spokesman said: "We have been very clear that we want a trade policy that is inclusive and transparent and which represents the whole of the United Kingdom.

"We will not be giving a running commentary on possible future trade policy".

The SNP said not consulting with the Scottish Government on trade deals could put the country's rising food and drink sector - currently worth £14bn - at risk.

The party's trade spokesperson Hannah Bardell MP said: "The international trade secretary wants to gamble with the future of our £14bn food and drink sector and give himself unbridled power to allow American chicken, beef and genetically modified foods into the UK, thus overruling the decision taken in Scotland and Wales to ban the production GM foods.

"This news comes the same week the Food and Drink Federation confirmed that Scottish produce has propelled the UK to export a record value of food and drink - with Scotch Whisky, salmon, and beer remaining the top three UK exports.

"Scottish salmon exports for the first half of 2017 reached a record value of £346m and the rise in beer exports is no accident given that the number of breweries in Scotland has more than doubled in the last six years.

"Liam Fox's letter confirms that the Tories' 'take back control' rhetoric will have the opposite meaning for Scotland as Westminster tries to centralise more power and overrule democratic decisions taken in Scotland.

She added: "With the next round of negotiations nearing, the UK government must meaningfully engage with the devolved governments to ensure that their interests are protected, and that protecting Scotland's place in the European single market and customs union matters, not least to everyone all around Scotland who are employed in the food and drinks sector."

Plaid Cymru said any move to freeze out Wales would be "disgraceful".

The party's Welsh treasury spokesman, Jonathan Edwards MP, said: "If the UK leaves the customs union enabling it to strike trade deals, it is vital that no trade deal is signed without the endorsement of the Welsh Government.

"Otherwise the British government could expose key Welsh economic sectors and our public services, effectively supplanting the devolved settlement.

"Within the customs union, member states and sub-national governments, like Wallonia in Belgium, can veto trade deals.

"It would be disgraceful if in post-Brexit UK, national governments within the British state are not able to defend their economic interests from Westminster politicians."