37. Storm Technologies - £56.6m

Last year was a corker for this Watford-based reseller, with turnover growing by upwards of 50 per cent and operating profit more than doubling to almost £2.4m. The firm holds partner accreditations from a clutch of A-brand hardware vendors, including HP, Lenovo, NetApp and IBM. It also partners with manufacturers including VMware, Cisco, Microsoft and Citrix.