The UK is on the verge of becoming a “broken kingdom”, a senior Tory has warned in the House of Lords.
Lord Cormack said the government underestimated “at its own potential peril, just what dangers surround us” post-Brexit.
He said the Westminster parliament could not behave as if it was the only legislative body in the UK.
Lord Cormack’s comments came as peers again called for a greater role for the devolved nations in the regulation of the internal market after leaving the EU.
Tory former lord chancellor Lord Mackay of Clashfern said that, while the UK parliament had the legislative competence to regulate the internal market, the devolved administrations also had a “fundamental interest” in it.
“It is wise to give them a voice in the way that it is exercised,” Lord Mackay said, urging consultations with the devolved administrations through the joint ministerial committee.
The calls came in resumed committee stage debate on the Internal Market Bill, which sets out the way that trade within the UK will work once it is outside the EU’s single market and customs union.
Peers have already indicated they will seek to strip out the most contentious parts of the Bill, which give ministers the power to breach the Brexit divorce deal brokered with Brussels last year.
Votes on those key clauses are expected next Monday and if the government is defeated it will set the scene for a showdown between the unelected chamber and the Commons.
Cabinet Office Minister Lord True said: “The government agrees that the internal market should be underpinned by an effective system of governance and consultation between the four administrations of the United Kingdom.”
But he argued the joint ministerial committee “was not the most appropriate nor most effective intergovernmental structure to engage on such technical considerations”.
The legislation will also establish an independent monitoring body, the Office for the Internal Market (OIM), aimed at supporting the smooth running of trade within the UK.
The body will sit within the Competition and Markets Authority (CMA) and provide independent, technical advice to Parliament and the devolved administrations on regulation that may damage the internal market.
Peers called for devolved representation on the CMA and a requirement that the administrations approve membership of the OIM.
Supporting the move, Lord Cormack said: “The United Kingdom is on the verge of becoming the broken kingdom.”
Ministers, he said, must have “proper regard” for the Scottish, Welsh and Northern Ireland administrations post-Brexit and ensure they all worked together.
Ulster Unionist Lord Empey said none of the devolved administrations supported the legislation and warned of conflict ahead if consensus was not achieved.
Labour former cabinet minister Lord Hain said the Covid crisis had “emboldened” the devolved administrations to make decisions significantly diverging from those made in Downing Street.
But, far from rewarding them for their competence, he said, the government was “exploiting Brexit as an opportunity to impose an autocracy on Great Britain, and potentially Northern Ireland as well, in respect of these internal market rules”.
Business minister Lord Callanan pointed out the devolved administrations would be consulted on appointments and warned the changes being sought by peers “would encourage a narrowing of expertise and risk the effective establishment of a panel at all”.
He said: “Consent would give each administration a veto, which could cause delays to and politicisation of appointments that would undermine the OIM from the outset.”