FTSE 100 firms sign up to Prompt Payment Code Recent FTSE 100 signatories to the code include Next, Petrofac and Sainsbury's. Businesses such as Amec, the engineering firm, and the miner, Rio Tinto, are not presently signed up to the code according to the latest prompt payment code list seen by The Sunday Telegraph. Government sources said that the list will be updated again on Monday and that some of the businesses could be in the process of signing up. Other FTSE 100 businesses have very little business in the UK and so are unlikely to join the code. "Cash flow is absolutely critical for small companies at any time, but even more particularly in these difficult economic times," Mr Fallon said. It is vital that people who are owed money should be able to get it quickly. The business minister said that signing up to the code ­allowed suppliers to see what all companies were doing in a sector which would encourage best practice. He admitted that 90 and 120-day payment terms were often "too long." "By signing up to the Prompt Payment Code we will be able to see what the competitors are able to do," he said. They [the longer payers] will come under pressure to match the terms offered by their competitors. I would hope they will be shamed by their competitors. John Walker, the national chairman of the Federation of Small Businesses, said that three quarters of their members had experienced late payment problems. Of those, 10pc were waiting for payments of more than £35,000.