The advice for some time in England has been to test twice weekly with lateral flow test.
On BBC news yesterday it was quietly announced that the advice in England was now to test before going to indoor crowded places. The webpage has been updated.
www.gov.uk/order-coronavirus-rapid-lateral-flow-tests
In England, you should take a rapid lateral flow test:
if you will be in a high risk situation that day
before you visit people who are at higher risk of severe illness if they get COVID-19
You are at higher risk of catching or passing on COVID-19 when:
in crowded and enclosed spaces
there is limited fresh air
In Scotland, Wales and Northern Ireland, you should take a lateral flow test twice a week.