Official Record Series 4 No 1174 General Permissions
Standardised European Rules of the Air – Exceptions to the Minimum Height Requirements
1) Definition
In these permissions:
a) ‘SERA’ means the Annex to Commission Implementing Regulation (EU) No. 923/2012 (‘the Standardised European Rules of the Air’ (and references to SERA followed by a number mean the corresponding provision of SERA)).
b) ‘licensed aerodrome’ means an aerodrome licensed under the Air Navigation Order 2009 or an aerodrome certificated under Commission Regulation (EU) No.139/2014 of 12 February 2014 and
c) ‘Government aerodrome’ means any aerodrome in the United Kingdom which is in the occupation of any Government Department or visiting force (as defined in article 255(1) of the Air Navigation Order 2009).
d) ‘notified’ has the same meaning as in article 255(1) of the Air Navigation Order 2009.
2) General (SERA.5005(f)(2))
a) The Civil Aviation Authority (CAA) permits, under SERA.3105 and SERA.5005(f), subject to the condition set out in subparagraph (b), an aircraft to fly elsewhere than as specified in SERA.5005(f)(1) at a height of:
i) less than 150 metres (500 feet) above the ground or water; or
ii) less than 150 metres (500) above the highest obstacle within a radius of 150 metres (500 feet) from
the aircraft.
b) The aircraft must not be flown closer than 150 metres (500 feet) to any person, vessel, vehicle or structure except with the permission of the CAA.
3) Approaches to Landing or Forced Landings
The Civil Aviation Authority permits, under SERA.3105, SERA.5005(f) and SERA.5015(b), an aircraft to fly below the heights specified in SERA.5005(f) and SERA.5015(b) if it is flying in accordance with normal aviation practice and:
a) practising approaches to land at or checking navigational aids or procedures at an aerodrome;
b) practising approaches to forced landings other than at an aerodrome if it is not flown closer than 150 metres (500 feet) to any person, vessel, vehicle or structure; or
c) flying in accordance with a notified procedure or when specifically authorised by the CAA in accordance with SERA.5015