LONDON, May 3 (Reuters) - Britain's latest climate action plan is unlawful, London's High Court ruled on Friday in a legal challenge by three environmental campaign groups over emissions targets.

Friends of the Earth, ClientEarth and the Good Law Project took legal action last year over carbon budgets set by the government in 2023 to meet Britain's target of net zero by 2050.

Britain's new emissions targets were set after a 2022 ruling that Britain had breached legislation designed to help reach the 2015 Paris Agreement goal of containing temperatures within 1.5 degrees Celsius of pre-industrial levels.

The three groups argued that the new plan is also unlawful, including because then energy minister Grant Shapps was not told of the risk that policies to reduce emissions could not be delivered.

Judge Clive Sheldon upheld four out of five grounds of their legal challenge in a written ruling on Friday. (Reporting by Sam Tobin)