The cost of policing the UN climate conference in Glasgow this November could exceed £200m, according to Scotland’s chief constable, who said it was “fanciful” to suggest that hosting one of the largest events ever staged in the UK would not have an impact on the wider community.

Iain Livingstone, the head of Police Scotland, told a board meeting of the Scottish Police Authority on Friday that accommodation for officers alone – many of whom will be drafted from forces in England and Wales – could cost “tens of millions”.

He added: “Candidly, it is my professional opinion that any suggestion that the climate change conference will not impact on the wider community of Scotland is fanciful.”

Warning of the “acute operational demand” posed by the climate conference and preparations around Brexit, he described Police Scotland’s capital budget as “derisory”.

Last week, Scotland’s auditor general, Caroline Gardner, told MSPs at a Holyrood committee that protecting officer numbers to deal with Brexit had taken policing budgets into a forecast deficit of £42m.

During the 12 days from 9 November, an estimated 30,000 visitors including potentially 200 world leaders will attend the UN’s 26th conference of the parties, known as COP26, at the Scottish Event Campus (SEC) on the River Clyde in the centre of Glasgow.

A report on policing the conference presented to the meeting for discussion also explained that the SEC would be handed over to the UN for the duration of the conference, becoming international territory – known as the blue zone – and thus subject to international law.

“Discussions are ongoing with senior law officers and the UN to determine how Police Scotland will record and investigate any crimes which occur within the Blue Zone,” says the report.

Scotland’s justice secretary, Humza Yousaf, has previously said he expects core costs including policing to be borne by the UK government.

• This article was amended on 23 January 2020. Because of an incorrect figure in a Police Scotland report, an earlier version said that an estimated 90,000 visitors were expected at COP26. Police Scotland have since amended that figure to 30,000 visitors.