Lawyer groups have voted to boycott contingency plans for Scotland’s courts during COP26 amid an ongoing row over legal aid.

The climate conference is expected to create a surge in arrests as activists gather to protest, with reports suggesting police officers have been told to expect up to 300 extra arrests per day.

Contingency plans are in place to deal with the subsequent increase in custody court cases, including a duty solicitor scheme and weekend custody courts in Glasgow, Edinburgh and Aberdeen.

However, bar associations from the three cities have all opted out of the plans, claiming poor rates of pay in legal aid have left the profession on its knees and unable to carry out the extra work.

The Scottish Government is offering an enhanced payment rate for the duty scheme and say it has been engaging with solicitors ahead of the conference.

However, the lawyers are unhappy that there will be no enhanced fee for existing clients who will also be processed at the weekend courts.

They also claim that decades of underinvestment in legal aid means that firms are unable to recruit and retain staff, with many drawn to higher salaries and better job security at the Crown Office, leaving them short staffed and unable to carry out the extra work.

Ian Moir, convener of the Law Society’s Criminal Legal Aid Committee, said the decision by the bar associations will cause serious disruption to the country’s courts at a time when the eyes of the world are on Scotland.

“Nobody wants to see a situation where people are in custody and can’t get a lawyer, but it needs to be resourced properly,” he said.

“The point has been reached where we can’t recruit anyone, we can’t retain anyone, we simply can’t do the sheer volume of work we’re being asked to do at the moment. And unless we get significant investment to allow us to offer better pay and conditions, there’s no way of fixing it.

“We are all struggling every day to cover the cases, we’re all doing our best but there’s not enough of us.”

He added that the only way to attract lawyers back to the COP26 scheme is to “come up with a commitment right now for a very substantial rise that will address decades of underinvestment in legal aid”.

The Glasgow Bar Association has written to justice secretary Keith Brown to confirm its position.

In the letter, GBA president Fiona McKinnon said that the issues with legal aid meant there was “no scope to take on more business, particularly when we are given less than two weeks’ notice of your proposals”.

She added: “We need not remind you that this is a conference that should have taken place last year. That we find ourselves in this position demonstrates the long-held belief that defence practitioners are always an afterthought.”

A Scottish Government spokesman said: “We have been engaging with the legal profession on an enhanced package of legal aid fees during the period of the COP26 conference and have responded positively to their proposals. We will continue to consider matters that they raise ahead of the conference.”