David Pardo, IT Skills Research: "As we have done in previous years, we gathered the revenues of companies with IT training businesses and excluded sales of training delivered outside the UK and non-IT related business from those companies that offer both types. We also exclude organisations whose revenue is derived principally from publicly funded training or from military or defence-specific IT training, training franchises whose revenues consist only of royalties, and training brokers and portals."

Financial results for some of these organisations are on public record. In those cases, we have used the actual turnover figure for their most recently reported financial year. For organisations whose turnover is not published, we have made our best estimate based on the information available to us.