The Crime Prevention Website


Over the next twelve months or so I will be putting together a whole new section on designing out crime which will show how defensible space can play a vitally important role in preventing crime.  So, without going into too much detail now, I will give you a basic description of what this is, using a terraced house as an example. 

Defensible space theory

Defensible space is defined as “a residential environment whose physical characteristics – building layout and site plan – function to allow inhabitants themselves to become key agents in ensuring their security”  Design Guidelines for Creating Defensible Space by Oscar Newman 1976 Published by National Institute of Law Enforcement and Criminal Justice (United States).  

Oscar Newman argued that good design can help the resident feel a sense of ownership and responsibility for the area around them, which will encourage them to defend it and that the more space that is under the control and influence of the residents the less there is for the criminal to operate in.  These ideas were adopted by the UK police’s initiative ‘Secured by Design’ in 1988, which has proved to be an excellent initiative whereby many thousands of homes have benefitted from this and other theories of designing out crime.  It has to be said though that the effectiveness of defensible space depends largely on the willingness and particularly the ability of the people in control of it to self police it, but by and large it seems to have worked well in the UK.

Oscar Newman identified four factors that create defensible space:

  • Territoriality  – which exemplifies the notion that a man’s home is his castle

  • Natural surveillance  – which is the ability of residents to be able to see what’s going on in their neighbourhood

  • Image  – the physical attributes of a development that make it defendable

  • Milieu  (surroundings) – making the most of a development’s location to places that will help to prevent crime

The hierarchy of space and the terraced house

There is a hierarchy of space in our built environment ranging from totally private and defendable space through to totally public.  The theory suggests that the more private a space is, the more control and influence a resident has over it.  Taking my terraced house as an example, the rear garden and the house can be described as totally private and I think you would agree that a resident would probably take some physical action to defend it. 

The walled front garden of the house could be described as ‘semi-private’ space, because although it is owned by the resident there is also an implied invitation for people to walk onto it, such as the milkman or the post woman.  Rules of behaviour apply to semi-private space of course and so if it was a sunny day and the milkman decided to sunbathe on the front lawn then the occupier would have something to say about it and has every right to do so because she owns the lawn and has control over it. 

Interestingly, an open planned front garden is not quite so easy to defend, because there is nothing in particular to define the changeover from public to private space and therefore nothing to stop people and dogs (looking for a nice toileting area) from walking on it.  You won’t be surprised to learn that lots of people get really fed up with others walking across their lawns to deliver leaflets door to door and others who let their dogs do their business on the grass.  I’ve always thought this was a flawed design, but something that can be improved using a simple picket fence. (You may need planning permission though).  Another solution I have seen comprises a white plastic chain about 100 to 150mm off the ground, loosely hung between tiny plastic posts.  Even this tiny physical barrier seems to reduce the amount of trespass over the lawn, but I suppose it could also be deemed a trip hazard – can you ever win?     

The public footpath and arguably the public road immediately outside the terraced house could be described as semi-public space.  The resident doesn’t own it, but can see it and probably parks a car on it.  Once again behavioural rules apply, even to this semi-public space, and so if a couple of yobs started mucking about right outside the house this behaviour would probably prompt a reaction from the resident.  They might call the police or they might intervene directly; and from the safety of their semi-private front garden could speak to the youths and ask them what they think they’re doing.

As you move away from the house down the road a bit, the space becomes fully public to the resident and she has no control over it whatsoever.  Bad behaviour down there might prompt a call to the police, but it is unlikely that she will intervene directly; this is for the residents down the road to do.

Defensible space has been used as an argument to create large gated communities (particularly in the USA ,South Africa and some far eastern countries), whereby a whole housing development is contained behind a fence or wall and thus is wholly private space; and I’m not so sure that this was what the late Oscar Newman was calling for.

Is defensible space an extension of personal space?  

It’s always struck me that the boundaries we place around our garden is an extension of our personal space.  Many of you will have experienced that uncomfortable feeling in a busy lift when a stranger has to stand within your personal space.  This personal space is normally that area within an outstretched arm.  It would be OK for your nearest and dearest to enter that space, but if a stranger does then the normal reaction is to take a step back and recreate the distance.  This uncomfortable feeling of your personal space being invaded is quite normal in Britain, but interestingly it’s not a problem in all countries or within all cultures where a close, personal approach by a stranger is quite normal. 

So, the imposition of a boundary fence is an extension of the defensive arm and one’s personal space, but the boundary doesn’t always need to be a physical boundary for people who obey behavioural rules.  There is a famous experiment involving a man lying on a busy beach.  Early on, when the beach was empty the man drew a circle in the sand to mark his spot.  The area circled was much bigger than he actually needed, but as the film shows, the line in the sand was respected by other beach users throughout the several hours of filming. Other beach users can be seen walking up to the circle in the sand and then walking around it, even to the point where one mum is seen grabbing her child to prevent it from entering the marked space.  The only person to enter the space during the experiment was a small boy retrieving his beach ball!

This use of the line in the sand, which is known as a ‘symbolic barrier’ can be found all around us.  The changes of a road surface texture or its colour as you drive off a main road into a housing estate and likewise, the use of different surface materials to mark parking spaces on the side of a street or bus lanes.   The police ‘do not cross’ tape strung across the highway keeps people away from the incident being investigated, but it’s hardly a ‘real’ barrier.

So, the message is less public space on housing estates and more private space.

For more information about defensible space please visit  The Institute for Community Design Analysis  

A PDF version of  Creating Defensible Space by Oscar Newman  can be downloaded from  this link