When online retailer So Organic started selling organic lifestyle products in 2004, founder Samantha Burlton couldn't have imagined it would end up in a protracted legal battle with one of the country's leading supermarkets.

Having registered the So Organic trademark in February 2005, Burlton and her business partner and husband, Stuart, were shocked to discover Sainsbury's had launched its own-label organic range under the SO Organic brand in October the same year.

"We flagged it up to Sainsbury's at an early stage and it chose to carry on regardless. We had a short and frank discussion and said unless it withdrew we would be pursuing legal action", says Stuart.

"It's a real David and Goliath battle. Even though we are smaller, we are morally and ethically in the right. It is our trading name and the name customers know us by.

"Initially Sainsbury's said it would only use it together with the Sainsbury's name as 'Sainsbury's SO Organic' and only for food products. Now it is trying to trademark the name SO Organic on its own and for all products, not just food."

The Burltons continue to fight their corner. They have a first-class legal team and a "very good" intellectual property lawyer.

The first trademark application made by Sainsbury's was dismissed in December last year, but following a change in the rules governing trademarks, So Organic is now awaiting a verdict from the Intellectual Property Office on Sainsbury's most recent application.

The Burltons say that the preliminary findings are that So Organic's opposition to Sainsbury's use of the name is likely to succeed.

"It shouldn't have got to this stage. We are a small company and this is an aggravation that takes management time away from our business," says Stuart.

A Sainsbury's spokeswoman adds: "We are progressing the application with the Patent Office."