11. Kcom - £268.8m

The Yorkshire-based firm is another whose business needs to be split into chunks for the purposes of this list. It is hard to tell exactly how big the company’s reseller and IT services arm is, but the bulk of the Kcom business (not to be confused with parent company KCOM) is built around Affiniti, the Cisco Gold partner brand formed from the carrier’s 2004 acquisition of VAR Omnetica.

Affiniti still files annual reports, which show the company as being a £250m operation in FY11. Its parent has since filed numbers for FY12, which show sales from its Kcom and Smart421 IT services brands standing at a combined £268.8m. This represents a decline of 2.9 per cent, but EBITDA for the year actually rose marginally to £26m.

The company has made a concerted effort in recent years to move away lower-margin product sales and break-fix services. Consequently revenue has dropped from £517.3m in FY08 to less than £400m in the recently completed year. But the positive effects on the bottom line are already in evidence.