UK air law is documented in ’The Air Navigation Order’ issued by the Civil Aviation Authority. You can view the ANO it in its entirety here: http://www.caa.co.uk/docs/33/CAP393.pdf
As model pilots we fall under “Small Unmanned Aircraft” and in some cases “Small Unmanned Surveillance Aircraft” and as such we are exempt from the vast majority of the Air Navigation Order. The articles that do apply to us are: 131, 138, 161, 164, 166, 167, 232
The following 4 are not really relevant to R/C and FPV and paraphrased descriptions are included here only for completeness – please open the PDF if you would like to read them in full.
131 = Dropping for the purposes of agriculture
161 = Power to prohibit or restrict flying
164 = A glider must not be winched or ground towed above 60 metres
232 except 232(2)(a) = CAA’s power to stop flying
The articles which are relevant to R/C, and FPV flying are: 138, 166 and 167.
Bold parts in the text below have been added by FPV UK to emphasise the key points.
Endangering safety of any person or property
138 A person must not recklessly or negligently cause or permit an aircraft to endanger any person or property.
Small Unmanned Aircraft
166 (1) A person must not cause or permit any article or animal (whether or not attached to a parachute) to be dropped from a small unmanned aircraft so as to endanger persons or property.
(2) The person in charge of a small unmanned aircraft may only fly the aircraft if reasonably satisfied that the flight can safely be made.
(3) The person in charge of a small unmanned aircraft must maintain direct, unaided visual contact with the aircraft sufficient to monitor its flight path in relation to other aircraft, persons, vehicles, vessels and structures for the purpose of avoiding collisions.
(4) The person in charge of a small unmanned aircraft which has a mass of more than 7kg excluding its fuel but including any articles or equipment installed in or attached to the aircraft at the commencement of its flight, must not fly the aircraft:
(a) in Class A, C, D or E airspace unless the permission of the appropriate air traffic control unit has been obtained;
(b) within an aerodrome traffic zone during the notified hours of watch of the air traffic control unit (if any) at that aerodrome unless the permission of any such air traffic control unit has been obtained; or
(c) at a height of more than 400 feet above the surface unless it is flying in airspace described in sub-paragraph (a) or (b) and in accordance with the requirements for that airspace.
(5) The person in charge of a small unmanned aircraft must not fly the aircraft for the purposes of aerial work except in accordance with a permission granted by the CAA.
Small Unmanned Surveillance Aircraft
167 (1) The person in charge of a small unmanned surveillance aircraft must not fly the aircraft in any of the circumstances described in paragraph (2) except in accordance with a permission issued by the CAA.
(2) The circumstances referred to in paragraph (1) are:
(a) over or within 150 metres of any congested area;
(b) over or within 150 metres of an organised open-air assembly of more than 1,000 persons;
(c) within 50 metres of any vessel, vehicle or structure which is not under the control of the person in charge of the aircraft; or
(d) subject to paragraphs (3) and (4), within 50 metres of any person.
(3) Subject to paragraph (4), during take-off or landing, a small unmanned surveillance aircraft must not be flown within 30 metres of any person.
(4) Paragraphs (2)(d) and (3) do not apply to the person in charge of the small unmanned surveillance aircraft or a person under the control of the person in charge of the aircraft.
(5) In this article ‘a small unmanned surveillance aircraft’ means a small unmanned aircraft which is equipped to undertake any form of surveillance or data acquisition.
At first it would appear that FPV flying would fall under article 167 for small unmanned surveillance aircraft because the ANO definition of an unmanned surveillance aircraft is as above in 167(5). However in situations where a camera is used for the sole purpose of controlling the aircraft the flight is not considered surveillance or data acquisition. CAP 722 (http://www.caa.co.uk/cap722) article 3.6 in Section 3 Chapter 1 page 4 refers to this, copied here: “The provision of image or other data solely for the use of controlling or monitoring the aircraft is not considered to be applicable to the meaning of ‘Surveillance or Data Acquisition’ covered at Article 167 for Small Unmanned Surveillance Aircraft.”
However if the video is captured in some way and used for other purposes the CAA considers the flight to have been for data acquisition and article 167 does apply.
CAA exemption from Article 166(3) for FPV fliers where the criteria of the exemption are met and the stipulations are followed: A full copy of CAA exemption 956 can be viewed here