Before timekeeping was standardised local times were based on local noon ie 12 o’clock was when the sun was highest in the sky, or, more easily determined with a sundial.

For example the historic Bromley House Library in Nottingham city centre has a brass meridian line dating from the 1820s which by showing the movement of the sun can show local noon with accuracy.

The development of the railways which needed standardised timekeeping , and the development of the telegraph which enabled instantaneous transmission of time signals across the country gradually did away with local times and introduced a standard time ( or time zones for those countries with a large east west spread).