Covid-19 rules for travelling to the UK will be relaxed for thousands of delegates attending the UN Cop26 climate summit in Glasgow in November.

Cop26 officials have set out conditions for the event, for which between 20,000 and 25,000 government delegates, media and campaigners from around the world are expected to flock to Scotland for talks on curbing global warming.

The summit – which will be attended by world leaders – is being billed as the last, best chance to limit global temperature rises to 1.5C to avoid the most dangerous climate change.

It was delayed from 2020 because of the pandemic and organisers have been keen to push for an in-person event this year to allow all countries to participate effectively and secure a successful outcome to climate negotiations, while ensuring it is a Covid-safe event.

Restrictions on travel to the UK and rules on quarantine and self-isolation will be reduced for delegates, while there will be strict testing protocols in place, including regular testing for all those attending the summit.

Delegates will also have to sign a charter agreeing to abide by the protocols for the summit.

Cop26 officials said full vaccination for the two week-long summit was strongly encouraged, and the UK had offered vaccines to registered delegates who would not be able to get jabbed by other means.

The UK is recognising all Covid-19 vaccinations as valid for the event, but officials also said they would not prevent people attending who had not been vaccinated.

A UK Government spokesperson said Cop26 was a necessary event, as the science was clear for the need to take immediate and far reaching action to have any chance of avoiding the devastating impacts of rising temperatures.

They added: “We know that achieving the ambitious global action needed to tackle climate change requires everyone sitting around the same table. To achieve this we have been working tirelessly to make arrangements for an in-person event.

“Hosting it safely is of the utmost importance to the UK. Like many recent international events, Cop26 will have to adapt in line with Covid.”

The spokesperson said details of how the summit would run were progressing after close collaboration with all partners, including public health officials in Scotland and England, the Scottish Government, Glasgow City Council and the UN’s climate body, the UNFCCC.

“We believe these arrangements strike a balance between allowing critical climate talks at this exceptional event to continue with representation from around the globe, while continuing to have measures in place to protect public health,” they said.

Under the regulations specifically for Cop26, delegates from red list countries will only have to quarantine in quarantine hotels for five days if they have been fully vaccinated, and for 10 days if they have not received the jabs.

There will be no requirement for Cop26 attendees coming from amber or green list countries to self isolate on arrival to the UK whether vaccinated or not, officials said. Most people are expected to come to the UK via London.

Under current rules, people cannot travel to England from red list countries unless they are British or Irish citizens or have the right to live in the UK, with the same rules applying to Scotland with some other limited exceptions.

Those that do arrive from red list countries have to quarantine for 10 days in quarantine hotels, even if they are double jabbed.

There are also requirements to self isolate for 10 days for those coming from amber countries who are not fully vaccinated via approved programmes in the UK, US or Europe.

While the red list can change, it currently includes dozens of countries, all of whom are expected to send delegates to Cop26, and some of which are among the most vulnerable to climate change.

The issue of who pays for the regime, including testing and quarantine hotels, has yet to be finalised. Isolation protocols during the event for those who test positive for the virus are also being finalised.

The rules for Cop26 have been signed off by the UK and Scottish governments, but Covid-19 protection measures for the summit could still change, officials said.