What is the difference between ser and estar?

'Ser' and 'estar' both mean "to be" but they have different meanings for different contexts. The most simple and general way to describe most uses is that 'ser' is used for jobs/occupations and longer-lasting/permanent situations than 'estar', which is used to describe positions, locations or temporary situations. For example -

Soy de Inglaterra = I am from England - which would always be the case, compared with

Estoy en Paris hoy = I am in Paris today - which is probably a temporary situation.

However, this is only a blanket description and does not follow for all uses of 'ser' and 'estar'!