76. Sabio

Key points

Revenue: £49.5m (+14%)

Net profit: 4.9%

Staff: 234

This Avaya Diamond partner claims that 19 years of consecutive growth have made it Europe's "leading specialist" in the support and delivery of contact centre technologies. An acquisition spree bankrolled by its private equity house, Horizon Capital, helped swell revenues by 14 per cent in its year to 30 September 2017. Since year end it has snapped up analytics specialist Bright UK. London-based Sabio's clients include the AA, SSE and Liverpool Victoria.