As originally designed and built, mtdvatbridge.uk was to be a Cookie Free Zone™. Cookies were not going to be used at all in the design of the site.
The original system worked quite well without cookies but as development progressed HMRC started to indicate that for 'Fraud Prevention' reasons we would have to start collecting data from our users and reporting back to HMRC the data with every request we make on behalf of our users. The fraud prevention page includes a link to the regulation. The document includes the following text :
One of the mandatory items is Gov-Client-Device-ID. This is :-
mtdvatbridge.uk is a web based system. Web browsers do have access to the registry and can't normally create hidden files so our only option is to create a cookie. We do set a cookie on your machine with a unique ID in it. The cookie is called 'Gov-Client-Device-ID'. This cookie is created every time you log in to mtdvatbridge.uk if it doesn't already exist. There is nothing to stop you cleaning up your cookie store and deleting the cookie if you want. We will create a new cookie next time you log in.You have no cookie set yet