This week Norfolk and Suffolk constabularies confessed that, replying to a freedom of information request, they had managed to release the personal details of 1,200 victims and witnesses of domestic abuse. The information was not readily visible but could be accessed by those with technical skills.

This came just a week after the Police Service of Northern Ireland admitted that it had similarly released, again in response to an FOI request, the names and ranks of its officers, along with the offices in which they were based.

It is hard to think of a more damaging leak of private data. For years during the Troubles police officers in Ulster were being picked off, sometimes shot on their doorsteps. It is vital, if we want police officers to risk their own safety in order to fight crime and terrorism, that they are afforded basic protection of their personal data.

Yet the police and other agencies of the state have a troubling habit of letting sensitive information slip. Earlier this month it was revealed that a cyber attack on the Electoral Commission had exposed the names and addresses of the entire UK electorate.

Yet the threat of data leakage or theft doesn’t seem to enter into the equation when the government decides to collect ever more data from us. Just look at the questions included on the last census – on our religion, sexuality, ethnicity and health – and ask yourself if you would be happy for that information to be available to all and sundry.

The government may have benign reasons for asking us for this information – which it does under pain of stiff fines for those who refuse – but anyone who is out to steal data may have very different intentions. The government’s ‘digital first’ strategy works on the assumption that if something can possibly be done in electronic form then it should be.

When you start from that position, it becomes natural to propose such measures as vaccine passports – an innovation which came very close to being forced upon us in the latter stages of the pandemic and which would very likely have evolved into a permanent record of our health, accessible to all kinds of public sector officials.

This magazine has consistently argued against the case of a compulsory – or de facto compulsory – ID card scheme on the grounds of basic liberty. We took that position when Tony Blair tried to use terrorism as an excuse to foist an ID card scheme on the public and we maintained it throughout the pandemic.

Blair is now back, flush with money from regimes from Kazakhstan to Saudi Arabia and with his own private institute which claims to have ‘embedded’ dozens of staff in governments in the world. He sees in Keir Starmer a man who is likely to win power but is short of ideas. The Blair institute will be only too happy to fill in the blanks.

Having almost succeeded in having his identity card scheme implemented by Boris Johnson, Blair is now proposing ID cards for children in the form of ‘digital learner ID’. The guise changes but the principle does not: to establish a society in which liberties and rights depend on having the correct accreditation from the state.

While an ID card might superficially offer protection against identity theft, that protection is only as good as the security of the system. If you can steal the data required to acquire a card, the concept becomes worse than useless. It becomes dangerous.

None of this is to say that it is not necessary for the government to keep some data on us. Criminal records need to be maintained. Her Majesty’s Revenue and Customs has to keep information on our income. We need the NHS to have records of our health. But there are principles which should always be applied to data collection by public authorities – that they only collect what is necessary. They should not seek to collate information on individuals any more than is required for the proper functioning of public services.

It will always be tempting for authorities to try to reach across to other bodies, and for the government to try to bring various databases together for the sake of efficiency.

Yet data that is collected for one purpose should not be used for another without there being a very good reason. That is a rule which the DVLA, for example, has broken when selling the home addresses of motorists to private parking firms.

It is hard to fathom the calamitous implications of the Northern Ireland police data leak. But it’s important to remember a general point: this fits a trend. Government lacks the competence to keep data safe. The imposition of identity cards – or any needlessly centralised records – presents an inherent risk to privacy and security as well as liberty.