If you want to film in a private building like someone’s, house or a company building. You would need to send them a letter asking for promotion. Most of the time you would offer them money for the use of the building.
If you want to film on local public properties like Read, land, building. So you would need to contact your local authority or council. On these website it has all of the contacts that your need to film in the UK. http://www.britishfilmcommission.org.uk/crew-facilities/locations/uk-agencies/
The police would need to be informed if you’re recording on a public highway or using special effects, explosives or fire arms (including replicas). You will also permission from the police offices.
Most of the info was find here http://www.britishfilmcommission.org.uk/crew-facilities/locations/filming-in-public-spaces/