Buyers of carbon credits should beware of the poor quality of some of the credits on offer, according to a new study of the market to be published by Environmental Data Services, an environmental research specialist.

Only 30 of 170 companies offering “carbon offsets” – carbon credits sold to companies or individuals for the purpose of balancing out the negative effects of their activities on the climate – were “quality” providers, ENDS said. Ten of the top scorers were based in the UK, which ENDS rated as “the global epicentre of quality offsets”. These included Camco International and EcoSecurities, both listed on Aim; Climate Care, bought recently by JPMorgan; Cantor CO2e, part of Cantor Fitzgerald; and the Carbon Neutral Company, a privately held company.