Well, Nottinghamshire Police has issued this advice:
Before you call
Before you call, make your own inquiries locally to trace the owner of the vehicle to ask them to move the vehicle. If the vehicle is linked to a local school, business or other venue (such as a pub or restaurant), also make some inquiries there.
If you wish to pursue a complaint of obstruction against the owner of the vehicle then you must be willing to make an official complaint to the police which could mean making a formal statement and may involve you going to court.
When you call
Call Nottinghamshire Police on the 101 non-emergency number, but note that they can only take action if someone is blocking your property and you need to access your property immediately.
Police cannot take action if someone is blocking your property but you do not need immediate access to leave your driveway at the time of calling, for example.
To report all other parking enforcement issues
It is important to comply with parking restrictions which are indicated by traffic signs and/or road markings. Infringements to these restrictions are enforced by local councils:
In the Nottingham city area: Contact Nottingham City Council on 0115 915 5555.
Outside of the Nottingham city area: Contact Nottinghamshire County Council on 0300 500 80 80.