Essex Drones have put together some information below but please feel free to contact us for any clarification .
The operation of the aircraft must not endanger anyone or anything.
The aircraft must be kept within the visual line of sight (normally taken to be within 500 m horizontally and 400 ft vertically) of its remote pilot (i.e. the ‘person in charge’ of it). Operations beyond these distances must be approved by the CAA (the basic premise being for the operator to prove that he/she can do this safely).
Small unmanned aircraft (irrespective of their mass) that are being used for surveillance purposes are subject to tighter restrictions with regard to the minimum distances that you can fly near people or properties that are not under your control. If you wish to fly within these minima, permission is required from the CAA before operations are commenced.
CAA permission is also required for all flights that are being conducted for aerial work (i.e. in very simple terms, you are getting paid for doing it).
The 'remote pilot' has the responsibility for satisfying him/herself that the flight can be conducted safely.
the full regulations can be found here
The aircraft must not be flown:
careful note should be taken that the collection of images of identifiable individuals, even inadvertently, when using surveillance cameras mounted on a small unmanned surveillance aircraft, will be subject to the Data Protection Act. As this Act contains requirements concerning the collection, storage and use of such images, Small Unmanned Aircraft operators should ensure that they are complying with any such applicable requirements or exemptions. Further information about the Data Protection Act and the circumstances in which it applies can be obtained from the Information Commissioner’s Office and website: www.ico.org.uk