Anyone aged 12 years or over who fishes for salmon, trout, freshwater fish or eels in England and Wales must have an Environment Agency Rod Fishing Licence.

A rod licence is required by law and allows you to use a rod and line to fish. Rod licences are issued by the Environment Agency and can be bought from any Post Office in England and Wales or by paying online.
Permits - often referred to as tickets or day tickets – are also required and give permission to fish in particular water or waters. They are issued by the owners, such as fishery owners, angling clubs etc. Fishing in Hertsmere:

Oakmere Park, Potters Bar High Street, has two large lakes with freshwater fish. You will need a permit from the Potters Bar and District Angling Club. Application forms can be collected from the Potters Bar Angling Centre, 248 High Street, Potters Bar, tel 01707 642947.