MI5 has requested that planners and architects keep some details of building designs top secret as part of the fight against terrorism.
An MI5 advisor told the AJ that by publishing detailed security measures in online planning applications, architects and planning authorities could be giving terrorists a 'head start'.
The officer added: 'It's a pre-emptive measure. It does not mean people do not get to see what a scheme will look like, but we have to take steps to prevent someone with hostile intent from accessing it. These people are bloody clever and we shouldn't be giving them gifts.'
The government has sent letters to chief planning officers throughout the UK asking planning departments not to publish plans which detail potential weak points in buildings, such as where bollards meet the foundations.