Tens of thousands of people, selected at random, will be invited to take part in a UK-wide forum on climate change this week.

However climate activists warn it lacks teeth and is working to a timescale which does not recognise the scale of the threat.

Climate Assembly UK, commissioned by six Westminster committees, will produce a report which is intended to be available for the next UK Parliament when it starts work after the general election.

From Wednesday a total of 30,000 letters are to be sent to addresses in England, Scotland, Wales and Northern Ireland asking people from all walks of life to join the body, although only 110 will eventually take part in the Assembly.

This representative group will then attend Climate Assembly UK over four weekends between late January to the middle of March next year in Birmingham. They will be given information about the global danger posed by climate change and asked to come up with radical solutions.

Six cross-party select committees at the House of Commons announced the assembly in June following a recommendation by independent advisors the Committee on Climate Change (CCC) which led to the UK becoming the first major economy in the world to adopt a target of reaching net zero emissions by 2050.

The Assembly will be asked to consider ways in which the UK can do this by reducing the amount of greenhouse gases it produces, and balancing its remaining emissions by absorbing the same amount from the atmosphere.

A UK Citizen’s Climate Assembly is one of the three main demands advanced by the Extinction Rebellion (XR) climate change campaigners. The group welcomed the new assembly warn it will be toothless and 2050 may not be an urgent enough target.

However Rachel Reeves MP, Chair of the Business, Energy and Industrial Strategy (BEIS) Committee said the move was significant. She said: “Adopting the net zero target was a major milestone for the UK, reflecting the strong cross-party support for action on climate change.

“We now need to set out a clear roadmap for the actions to achieve net-zero. It’s very clear that we will all need to play a part in meeting this target and that we all share a responsibility to future generations to do so.”

She said it was essential that policy makers worked with the public to find equitable solutions and ensure public support for any changes. “The Climate Assembly UK will advise Parliament on how people want us to meet the net zero target, and suggest policies that the Government can implement.”

Citizens’ assemblies have been used all around the world by bringing people from a range of backgrounds together to discuss important issues. The Scottish Government’sown Citizens’ Assembly of Scotland began meeting last month to address questions about the way forward for this country in the 21st Century.

A representative sample of the population will be selected from those who respond to the invitation letters, with 110 people taking part in the assembly. Mel Stride MP, Chair of the Treasury Committee said, “Public concern around climate change is as high as it has ever been and this is a chance for people from all parts of society to come together, to decide how we as a country can best meet our net zero emissions target.”

Key themes to be discussed at Climate Assembly UK will include how people travel, what people buy and household energy use. The six select committees said they would then use their conclusions as a basis for more detailed work.

It will also be debated in the House of Commons - however Extinction Rebellion said it needed official government endorsement and a commitment to implement any recommendations it makes.

Linda Doyle, XR Citizen’s Assembly spokeswoman Linda Doyle said it was an important step. But she added: “Waiting 30 years to reach zero net carbon emissions is a death sentence to people around the world and in the UK - it gives us a higher chance of breaching irreversible tipping points as the climate breaks down.”

She said it was essential the public had a proper chance to design the future they want for themselves, but XR is ‘devastated’ at the 2050 target.

Ms Doyle added: “This Citizens’ Assembly is advisory, toothless in other words. The Government is free to ignore the recommendations of the Citizens’ Assembly. Extinction Rebellion demands a Citizens’ Assembly that is endorsed by government and has real decision-making power.”