Millions of Taxpayers’ Voiceprints Added to Controversial HMRC Biometric Database

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The fact that the voiceprints of more than 2 million people have been added to HMRC’s Voice ID scheme since June 2018, to add to the 5 million plus other voiceprints already collected, has led to complaints and challenges to the lawfulness of the system by privacy campaigners.

What HMRC Biometric Database System?

Back in January 2017, HMRC introduced a system whereby customers calling the tax credits and Self-Assessment helpline could enrol for voice identification (Voice ID) as a means of speeding up the security steps. The system uses 100 different characteristics to recognise the voice of an individual and can create a voiceprint that is unique to that individual.

When customers call HMRC for the first time, they are asked to repeat a vocal passphrase up to five times before speaking to a human adviser.  The recorded passphrase is stored in an HMRC database and can be used as a means of verification/authentication in future calls.

Got Voices By The Back Door Said Big Brother Watch

It has been reported that in the 18 months following the introduction of the system, HMRC acquired 5.1 million people’s voiceprints this way.

Back in June 2018, privacy campaigning group ‘Big Brother Watch’ reported that its own investigation had revealed that HMRC had (allegedly) taken 5.1 million taxpayers’ biometric voiceprints without their consent.

Big Brother Watch alleged that the automated system offered callers no choice but to do as instructed and create a biometric voice ID for a Government database.  The only way to avoid creating the voice ID on calling, as identified by Big Brother Watch, was to say “no” three times to the automated questions, whereupon the system still resolved to offer a voice ID next time.

Big Brother Watch were concerned that GDPR prohibits the processing of biometric data for the purpose of uniquely identifying a person, unless the there is a lawful basis under Article 6, and that because voiceprints are sensitive data but are not strictly necessary for dealing with tax issues, HMRC should request the explicit consent of each taxpayer to enrol them in the scheme (Article 9 of GDPR).

This led to Big Brother Watch registering a formal complaint with the ICO, the result of which is still to be announced.


Big Brother Watch’s complaint may have been the prompt for changes to the Voice ID system. In September 2018, HMRC permanent secretary John Thompson said that HMRC felt it had been acting lawfully, by relying on the implicit consent of users.  Mr Thompson acknowledged, however, that the original messages that were played to callers had not explicitly stated it was possible, or how, to opt out of the voice ID system, and that, in the light of this, the message had been updated (in July 2018) to make this clear.

Mass Deletions?

On the point of whether HMRC would consider deleting the 6 million voiceprint profiles of people who registered before the wording was changed to include ty opt-out option, Mr Thompson has said that HMRC will wait for the completion of the ICO’s investigation.


Big Brother Watch has highlighted a backlash against the Voice ID system as indicated by the 162,185 people who have called HMRC to have their Voice IDs deleted.

What Does This Mean For Your Business?

Even though many businesses and organisations are switching/planning to switch to using biometric identification/verification systems in place of less secure password-based systems, it is still important to remember that these are subject to GDPR. For example, images and unique Voiceprint IDs are personal data that require explicit consent to be given, and that people have the right to opt out as well as to opt-in.

It remains to be seen whether the outcome of the ICO investigation will require mass deletions of Voice ID profiles.  Big Brother Watch states on its website that if people are not happy about the HMRC system they can complain to the HMRC directly (via the government website) or file a complaint about the HMRC system to the ICO via the ICO website (the ICO is already investigating HMRC about the matter).  HMRC has said that all the voice data is stored securely and that customers can now opt out of Voice ID or delete their records any time they want.

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