The Heartland Institute, which questions human-made climate change, has established a new branch in London.

The decision to allow Novatek to attend the flagship conference was described as “disappointing” and “disturbing” by campaigners.

Critics say the controversial GWP* method – which New Zealand appears close to adopting – is “open to significant abuse”.

Campaigners warn that the UK will face “pressure from American fossil fuel interests” to slow its energy transition.