I served my time in Scotland with the power company (SSEB, now Scottish Power). Did two years at their training center, followed by two years "on job" training.
First year, went to technical college on day release, one day a week. Two days a week on subsequent years, and also two evenings a week in years three and four.
Finished up with City & Guilds exam certificates (236 parts 1,2 & C and 236 Supplentary electronics), which they assured me would be recognised worldwide. However when I came to the USA, nobody here has ever heard of City & Guilds!
In my opinion, a very good grounding in the field, but there is not a day goes by where I don't learn something new.