Two of the UK's top experts on Brexit have condemned the Scottish Tories for "ad-hominem" attacks and lowering the tone of debate.

Dr Kirsty Hughes and Dr Katy Hayward yesterday launched a new report looking at the impact of leaving the EU on both Scotland and Northern Ireland and warning the process could undermine devolution in both countries. "Devolution has been seen more as an irritation than as a central concern in planning Brexit," they said.

Their paper provoked an aggressive response from the deputy leader of the Conservatives, Jackson Carlaw, who described it as "lurid".

Experts: Brexit is undermining devolution and powers repatriation is shambolic

As The Herald reported, he added: "This smacks far more of personal prejudice than any meaningful contribution to the debate and will, I am confident, be comprehensively disproved by the reality of what is actually negotiated and agreed."

The two experts in a letter in The Herald rejected what they called Mr Carlaw's "astonishing and unfounded attack". They wrote: "We are senior researchers in our fields, with decades of experience and international reputations; as such, we are happy to discuss and debate our analysis on a serious basis.

"But if politicians prefer ad hominem attacks - so contributing to a lowering of standards in public debate - rather than engaging with the substance of the issue, it perhaps suggest they do not have a substantive response to make."

Experts: Brexit is undermining devolution and powers repatriation is shambolic

Dr Hughes runs the Scottish Centre on European Relations and has specialised in the Scottish dimension of Brexit in recent years after a career working in some of the most prestigious think tanks in the UK and EU, including Chatham House in London and Centre for European Policy Studies in Brussels.

Dr Hayward is a reader at Queen's University, Belfast, and an authority on some of the knotty Irish border issues arising from Brexit. She has been researching the EU's role in the Irish peace process for 20 years.