An ATZ Is Controlled Airspace Too!
Did you realise that ATZs are every bit as much controlled airspace as the Class A and D airspace that we all do our best to avoid?

Aerodrome Traffic Zones (ATZ) surround "licensed aerodromes". A licenced aerodrome is one "where flights for the purpose of the commercial air transport of passengers or the public transport of passengers, and/or flying training in aircraft above specified maximum total weights authorised take place." [CAA Aerodrome Licencing Background Information].
What does this mean in practice?
For many licensed aerodromes in quiet rural areas away from the main regional airports, it may just mean that they have a few Cessnas doing a handful of flying lessons. This is the level of activity that many of us have grown up to associate with licenced aerodromes.
However, increasing numbers of these licensed aerodromes are growing and trying to increase their revenue. Many of them are burgeoning regional airports with aspirations to become the next Doncaster, or even Glasgow International. They may have frequent movements of commercial aircraft and Bizjets (a Bizjet can be anything up to a small airliner size) all of which fly at high speeds and have limited lookout.
The last thing they want is an unknown glider ambling about in their vicinity. In fact, the more issues these airports have with unknown traffic, whether infringing their zone or even just close by, the more likely it is that aerodromes will apply for their own Class D airspace.
Until recently, exemptions and UK legislation have allowed applications for small areas of Class D airspace. However, now that we are tied to European regulation, any Class D proposal will have at least the same footprint as the recently established Norwich CTR.
Just imagine how a new control zone of that size would affect your cross country flying if centred on an ATZ close to your club.

So, the advice is to remember that: 1. ATZs are controlled airspace and must be
respected. 2. Traffic can be dense both within the ATZ itself
and within a 5-10nm vicinity of the airfield 3. Even if you don't have an RT licence, please
‘listen out’ on the frequency if flying in the vicinity of an ATZ. If you hear something that is relevant to you then please make yourself known to ATC, eg "Sandfield Approach, glider S1 is circling between 2000 and 3000ft over Marshford village then flying west" 4. Do not enter an ATZ without contacting ATC first. 5. Airfields with an Instrument Landing System (ILS), shown on the half-mil map by a narrow band of chevron marks radiating out from the ATZ, deserve extra care - the chevrons show exactly where commercial traffic is likely to line-up on approach.
The reputation of our sport is on the line.
AERODROME TRAFFIC ZONE (ATZ), is airspace from the surface to 2000ft AAL within a circle centred on the notified mid-point of the longest runway, radius 2.0NM (RWY<1850m) or 2.5NM (RWY>1850m), where Mandatory Rules apply.