It is forbidden isn't it? It's not one of the legitimate reasons for leaving the house. My angling days are behind me but I do understand why people find it relaxing, enjoyable etc but it's not 'exercise'.
From the gov.uk 'full guidance'...
Quote:
You should only leave the house for very limited purposes:
shopping for basic necessities, for example food and medicine, which must be as infrequent as possible.
one form of exercise a day, for example a run, walk, or cycle - alone or with members of your household.
any medical need, including to donate blood, avoid or escape risk of injury or harm, or to provide care or to help a vulnerable person.
travelling for work purposes, but only where you cannot work from home.