53. Ensono

Revenue: £80.3m (+5%)

Staff: 311

Built on the acquisitions of Attenda, Inframon and Amido, Ensono's UK subsidiary turned over £80.3m in calendar 2020 (2021 accounts were overdue as this report went to press). The Chicago-based AWS, Microsoft, Google and IBM partner employs 2,900 staff globally. In July 2022, it appointed Howard Malloy as its new European leader following the departure of Hannah Birch. The KKR-backed outfit recently bagged AWS Mainframe Modernization Competency status.