This page explains how you can apply to come to the United Kingdom to film on location without a work permit.
Although it is not mandatory, in most cases non-European Economic Area (EEA) nationals should apply for entry clearance before travelling to the United Kingdom. For further information on this you should see the visa services website. You must be outside the United Kingdom to apply for entry clearance.
If you have successfully applied for entry clearance, you will have visa that allows you to stay for up to 12 months.
If you are refused entry into the United Kingdom, you will be told in writing the reasons why you have been refused entry and if you have any rights of appeal.
Visa services, Foreign and Commonwealth Office, King Charles Street, London, SW1A 2AH. If you are outside the United Kingdom you should contact you nearest British diplomatic post.