Some major retailers and independent stores have introduced AI body scans, CCTV or facial recognition equipment to identify crimes, such as shoplifting on their premises.

But civil liberty campaigners are warning the public are being put on "secret watchlists and electronically blacklisted" from their high streets.

The government says while commercial facial recognition is legal, its use must comply with strict data protection laws and be used transparently.

Watch as BBC's Jim Connolly puts the technology to the test at an independent Post Office.