Depending on which two places you are comparing, places in the UK can be up to half an hour ahead of Spain. In other words there is a time difference of approximately 30 minutes, though this varies from place to place. The time zone that a place is in is dependant entirely on its longitude, due to the fact that the longitudinal lines define the time zones. Greenwich was defined as being at 0 degrees longitude for historical reasons (this line is called the "Greenwich Meridian"), and the east of Spain (places such as Valencia) have very nearly the same longitude as Greenwich so are therefore in the same time zone, and so there is no time difference between Greenwich and Valencia.
However, Spain is a large country, and a place like Sevilla is at about 7 degrees west, so will be in a different time zone to Greenwich. Any good globe will have a dial where time difference can be estimated, and by my globe, the time in Sevilla is about 30 minutes earlier than in Greenwich, in other words Greenwich is ahead of Sevilla by 30 minutes. If you don't have a globe, here is a calculator you can use to find the time difference between places: www.timedial.net/world-time-difference-calculator/
However, Spain is a large country, and a place like Sevilla is at about 7 degrees west, so will be in a different time zone to Greenwich. Any good globe will have a dial where time difference can be estimated, and by my globe, the time in Sevilla is about 30 minutes earlier than in Greenwich, in other words Greenwich is ahead of Sevilla by 30 minutes. If you don't have a globe, here is a calculator you can use to find the time difference between places: www.timedial.net/world-time-difference-calculator/
