Government Economic Service
For a flavor of what you can do as a Government Economist, this site provides some mini career stories of what it is like working for the Government Economic Service and the varied opportunities available.
https://www.gov.uk/government/news/our-economists-talking-about-the-exciting-opportunities-in-the-government-economic-service
The Economics Network
The Economics Network offer advanced resources suitable for AS and A Level students.
https://www.economicsnetwork.ac.uk/resourceindex