Whats the legal width for a road on to my business premises? -

ive poeple parking on my road and obstructing my gateway whats the legal width

There is no legal width.If people are obstructing your driveway or gates then call the police and have them removed.

There is no legal width in British Law. You could contact the Highways Agency and see if there is anything they could do, maybe with white lines or restricted parking.