9. World Wide Technology

Key points

Revenue: £500m (+56%)

Net profit: N/A

Staff: 80

This US-based Cisco, VMware, NetApp, Dell EMC and HPE partner has more than 5,000 staff and turned over $10.4bn in 2017, making it the second-largest global reseller by our estimates. Sizing its UK business is problematic since it does not publicly divulge its local numbers, but at the time it opened its Canary Wharf office in 2013, WWT said it was already conducting $100m in business in Europe. Based on market sources, we estimate its European revenue now stands at approaching $650m (£500m), the lion's share of which is drawn from financial service and service provider customers in the UK.