The Part Wall Act 1996 has bee effective throughout England and Wales since 1st July 1997. This Act comes under Civil Law and is therefore not administered or controlled by either the Planning or Building Control Departments.
You may need to refer to the party walls legislation if you plan to build your conservatory:
It is always advisable to inform your neighbours before you undertake any work as any construction will cause inconvenience and access problems. Construction work on properties can sometimes turn in to a contentious issue, regardless of how well you get on with your neighbours so by keeping them well informed reduces the chances of any problems further down the line. Please ensure you take expert advice during your planning regarding the Party Walls act before any construction begins.
To down load a copy of the party wall act click here (http://www.communities.gov.uk/publications/planningandbuilding/partywall)