I remember about 35 years ago, starting to work as a graduate recruit for ICI at Welwyn Garden City (no manufacturing on the site any more at the time; it was primarily middle and senior management, sales and marketing departments and computing staff).
They worked a form of informal flexitime: in my part of the busness, the senior manager explicitly said that if they didn't trust you to work your hours, then they shouldn't have employed you. As a graduate recruit, I was expected to work more than my contracted hours on occasion, but my immediate line manager always said to me that if I was excessively working long hours and was nevertheless working efficiently, then all I was doing was masking the need to for extra resource.
Some areas did official clocking in, while others didn't (depended on the role).
Colleagues told me of the story about the time that a new Jobsworth started (I think in HR) who took it upon himself to monitor the time that everyone came in and to let their managers know that their subordinates should be disciplined for coming in "late"
.
That night, for the first time forever
, there was a traffic jam of people leaving at 5pm on the dot. Up until then, most people left some time between 5.30 and 6 - but if "they" were going to quibble about 5 minutes here and there, when most people worked significantly more than required, then they sure as hell weren't going to work a minute more than required.
That particular Jobsworth was moved elsewhere 