Internet filtering and blocking policies
Request ID: FOI-2716-1718
Date published: 19 January 2018
You asked
We would like to know, in relation to your publicly accessible Internet networks, or Internet networks for your clients:
1) The categories of content blocked or filtered, eg:
a)Security or Malware
b)Content types, eg adult, alcohol etc
c)Statistics relating to the requests blocked or filtered, eg how many site requests filtered or blocked per category
2) Monitoring requirements you have for users, eg if you record or may record their Internet usage
3) The supplier of your blocking or filtering software
a) Eg, Sophos, Forcepoint, Palo Alto etc
We answered
Our Ref: FOI-2716-1718
Thank you for your request received on 22 December 2017 asking for information about our internet filtering and blocking policies
Your request has been considered in accordance with the requirements of the Freedom of Information (FOI) Act and our information access policy. We do hold the information you require.
However, in accordance with the FOI Act we are not obliged to supply this information as it is subject to a statutory exemption to the right of access to information under Section 24 (National security).
In this instance the exemption applies as disclosure of information on the type of categories we do or do not allow, the products we use to filter traffic, or how we monitor internet traffic would make it easier to circumvent our controls. This would make it more likely that someone is able to compromise a system, website, or steal personal data. Whilst we make no suggestion that you would use this information for anything other than you own personal interest, disclosure of this information to you has to be regarded as a disclosure to ‘the public at large’.
The London transport system is a critical piece of national infrastructure and as such we employ rigorous safeguards to protect it from cyber attack. Like other organisations we are subject to regular attempted cyber attacks. These attacks are unlawful under the Computer Misuse Act, and whilst the motive is not always apparent, we are aware of the risk to critical national infrastructure that may result from a successful attack.
We consider that releasing information about our filtering and blocking polices would be likely to prejudice our efforts to prevent and detect future cyber attacks and undermine our ability to safeguard the London transport network.
The use of these exemptions is subject to an assessment of the public interest in relation to the disclosure of the information concerned. We recognise the need for openness and transparency by public authorities, but in this instance we consider that there is greater public interest in safeguarding our information systems and protecting the integrity of the London transport network.
Please see the attached information sheet for details of your right to appeal.
Yours sincerely
Gemma Jacob
FOI Case Officer
FOI Case Management Team
General Counsel
Transport for London
[email protected]
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