Cyber Essentials is the UK government-backed certification scheme covering five baseline controls: firewalls, secure configuration, access control, malware protection and patching. Cyber Essentials Plus adds independent technical testing. Many UK public-sector contracts require one or the other from suppliers.
It is deliberately a floor, not a ceiling: a starting standard every supplier should clear rather than proof of advanced security. Buyers evaluating workplace software in the UK typically look for Cyber Essentials as the baseline and ISO 27001 as the mature system above it.