Mr Fothergill's marketing manager Ian Cross said it supplied £400,000 of product a year to Focus. "It couldn't have been worse timing. We had put in a lot of stock at Easter. They had as much in as they would get," he added.
Cross said Focus would sell off stock to raise cash for creditors but added: "As far as we are concerned, it has gone. It leaves a hole we have to fill."
B&Q has bought 31 Focus stores for £23m and Wickes has acquired 13 for £8.4m. Homebase and discount stores are looking at others.
One supplier, who did not want to be named, said: "Focus claimed not to have deviated on payment days with suppliers and with minimal credit insurance several key suppliers will have had a bad day."
Supplier Scotts said the situation was "fluid and ongoing" and would not comment further. Forest said it had credit protection in place, while Sinclair said it had limited exposure.