18. RM

Key points

Revenue: £185.9m (+11%)

Net profit: 6.9%

Staff: 1,734

RM's heritage may be in building PCs for schools, but it now draws more revenues from its curriculum resources arm, RM Resources, than it does from ICT. For its year to 30 November 2017, RM's revenues rose 11 per cent to £185.9m, but ICT arm RM Education, which supplies ICT software and services to 7,000 UK schools and colleges, saw sales slip eight per cent to £70.6m.