The Crime Prevention Website


As a rule of thumb, if a window can be forced open by a thief standing on a flat surface it definitely needs to be locked.  This would include all ground floor and basement windows and those accessible from open deck access (walkways) in blocks of flats and windows over flat roofs; any window in fact that is ‘easily accessible’. 

The police Secured by Design guidance for new homes states the following about what is ‘easily accessible’:   ‘Common sense dictates that easily accessible windows or doorsets are those that can be accessed via a flat roof, balcony or other similar structure, e.g. external supporting or decorative balcony detail.  ‘Easily accessible’ in this context also means that access can be gained by two persons (one climbing, one assisting) without the use of a climbing aid, such as a ladder’.   This is good advice and I would also add that windows on the first floor and above that are adjacent to external waste pipes, such as those coming from a bathroom or toilet and and rainwater pipes should be locked.  As a kid, I used to climb through a waste pipe if I got locked out, because my mother used to leave the bathroom fanlight window open to air the room.  I could quite easily climb the waste pipe, put my hand through the open fanlight and open the larger, unlocked casement and climb in, sometimes head first into the toilet pan.

Rainwater pipes can be rendered useless for the purpose of climbing by fitting a device known as a 'Kelly Coupling'. A Kelly Coupling incorporates a stainless steel compression spring within a long lasting rubber sleeve, which replaces a small section of an existing or new rainwater pipe.  When a thief attempts to climb up the pipe the spring compresses and the pipe to which it is attached decouples from the joint above. After a failed attempt to climb the pipe, the pipe can be easily refitted. Warning notices (supplied) must be displayed. See Kelly Coupling in our Directory

If you are going to replace your windows with new secure ones then the advice above will help you decide which windows need to have enhanced security.  (See  Windows of enhanced security)

New information

Below is some further, recently added, information posted in response to recent questions from Clare W and Brian G

What is a secure window?

I define a secure window as either:

  • A window that has been ‘designed’ to be secure, which has been fully closed with the locks engaged and the key removed (see PAS 24:2016 above), or
  • A window that has been fitted with sufficient locks for the risk, which has been fully closed with the locks engaged and the key(s) removed
  • A fixed window that does not open
  • A window protected by a security device, such as a shutter, grille, gate or a secure secondary glazing system

This definition does not take account of the glass used to glaze the windows, which is dealt with in Glazing for Domestic Security or the many other factors that can affect risk - see below:

Does the position of a window make it more or less secure?

The relative position of a window does make a difference in terms of whether it needs to be fitted with locks etc.

EXAMPLE: A four bedroom house with front accessed basement, open side access, full-width flat roof rear extension and loft conversion

An estimation of risk – 1 being the highest risk

  1. Any window left open, including inaccessible ones (as an open window may cause the thief to return with ladder)
  2. Rear ground floor windows
  3. Side ground floor windows
  4. Front basement windows
  5. Front ground floor windows
  6. Rear first floor windows above flat roof
  7. Side first floor windows near to climbable pipes
  8. Front first floor window
  9. Rear loft window
  10. Side loft window
  11. Front loft window

Please note that many factors will affect the risk of a particular window being used to gain entry and as you can see from the list below ‘position’ is just one of them.

  1. Position of window – floor level, rear, side or front
  2. Type of window: Sash, casement, louvre, leaded light, rooflight
  3. Intrinsic security of the window, i.e. Certificated to PAS 24:2016
  4. Material used in its construction: Timber, uPVC, Aluminium, Steel, Fibreglass, Composite
  5. Type of glazing: Toughened, Float, Laminated, Filmed, Wired, Leaded
  6. Quality, type, number and position of security locks
  7. Whether protected with shutters, grilles or gates or a secure secondary glazing system certificated to an appropriate security standard
  8. Whether intrusion will trigger an alarm detector
  9. Surveillance over the window by potential and responsive witnesses
  10. There are probably others!

Updated February 2015, September 2017