The organics lobby has received a fillip from a landmark piece of research, providing relief for the Soil Association (SA) from a row on restaurant certification.

Major Swiss research declared the system 'more efficient' and 'kinder to the environment' than its conventional rival, while the SA was criticised for a policy that will force restaurants to become certified to sell organics.

The Research Institute of Organic Agriculture – in Frick, Switzerland – study was a boon for a sector which has come under fire for failing to prove its claims in the past.

SA spokeswoman Sue Flook said: 'It's one of the longer–term pieces of research and it's very useful for us. It's a really good boost for our organisation.' But the SA ended up taking the rough with the smooth as it came under fire from one of the leading champions of organic food – TV chef Antony Worrall Thompson, who owns the popular Notting Grill restaurant in west London.

The gastronome dismissed new EU guidelines – to be implemented by the SA – as 'a nonsense'. The regulations are designed to prevent fraudsters selling food as organic when it is not, but could costs eateries thousands of pounds as they will now have to become certified if they wish to call themselves organic restaurants.

'The rules are totally wrong,' Thompson told the Observer. 'The people who made them understand farms and factories, but they don't understand restaurants.

'If I offer organic chicken and show my customers an invoice for it, why should I need a licence as well?' Flook admitted the chef regularly promotes organic food on his television shows and said the SA had little choice but to carry out the EU's bidding – which it did not agree with.

She said: 'He does support organics, and says what he sees fit, but we have to stick to regulations under EU law.

'The EU laws are too strict and we are looking to work with restaurants [to see what we can do].' But despite of its apparent unease at European policy, the SA stands to make a considerable amount from the certifications – between £300 and £5,000 per visit, depending on restaurant size and turnover.

But Flook defended the charges.

'The farmers and producers pay to be certified and we have to cover our costs – it's very thorough, and we can't do it for free,' she told the Journal. 'The restaurants haven't paid anything towards that process so far and we have to check the restaurants are keeping their integrity on organic food and haven't been preparing organics in areas where GM has been prepared. In certain restaurants we wouldn't allow certain fly sprays to be used for example.'