A PROFESSOR of law has said it’s “debatable” whether the indirect effects of the Scottish Government’s Gender Recognition Reform (GRR) Bill on the UK wide Equality Act is “sufficient to trigger” the use of Section 35 of the Scotland Act 1998 by Westminster.

Aileen McHarg, Professor of ­Public Law and Human Rights at ­Durham Law School, told the ­Sunday ­National: “The GRR Bill doesn’t ­directly change the Equality Act; it has ­consequential effects on it via ­changing the criteria for getting a Gender Recognition ­Certificate (GRC), which is regarded as ­changing legal sex for the purposes of the Equality Act (and other ­purposes).

"It is certainly ­debatable whether those indirect effects are sufficient to ­trigger the use of Section 35.”

She added: “The phrase in ­Section 35 is that the Bill makes ­‘modifications of the law as it applies to reserved matters’, which is somewhat obscure – and since the power has never been used before, there is no judicial ­guidance on what it means.”

McHarg spoke after a furore last week when Secretary of State for Scotland, Alister Jack, announced he was going to use the so-called ­Section 35 “nuclear” option on the GRR Bill which was passed ­overwhelmingly with cross party support by the ­Scottish Parliament.

Any bill passed by the Scottish ­Parliament that Westminster believes could relate to a “reserved” matter is usually referred directly to the ­Supreme Court for checking under section 33 of the Act.

The move has been dubbed a ­nuclear option because it gives the Scotland Secretary the power to block any legislation passed by ­Holyrood, even if it is a devolved matter.

To be able to do this, Jack has to prove the Bill being blocked must make “modifications of the law as it applies to reserved matters” and must have “reasonable grounds to believe it would have an adverse effect on the operation of the law as it applies to reserved matters”.

Outraged supporters of the GRR Bill claim Jack has failed to do this and First Minister Nicola Sturgeon has vowed to fight his move with a judicial review.

The UK’s top pollster, John ­Curtice, said he would be “surprised” if there were any sustained impact on ­support for independence.

Curtice pointed out that two opinion polls before Christmas suggested the public in Scotland were two and three to one against the changes in the GRR Bill which would allow ­people to change gender more easily.

“Some people will be upset about what the UK Government are doing even if they are not that happy about the Bill but given how far behind you are starting from in that matter of public opinion I would be surprised if there is any sustained impact on support for independence,” said Curtice.

“Independence supporters could develop a story that says ‘this UK Government spends money in ­devolved areas, it has basically torn up the Sewell Convention in many ­respects, it won’t allow us to have a ­referendum and now they are trying to impose further limits on ­Parliament’ but to be honest I think the SNP have not always been that successful so far in persuading voters of this narrative. The question is can the SNP join the dots?”

He added that it may look bad for the Unionist campaign if Sturgeon wins her court bid.