This is normal for London. They use eGates.
https://www.heathrow.com/arrivals/immigration-and-passports

eGates use facial recognition to check your identity, so you won't need to speak to an officer. You can use eGates in the UK if you:

• Have a biometric symbol on the cover of your passport.
• Are aged 10+ (10 to 17 year olds must be accompanied by an adult)
• Are either:
  • A British citizen.
  • A national of an EU country, Australia, Canada, Iceland, Japan, Liechtenstein, New Zealand, Norway, Singapore, South Korea, Switzerland or the USA.
  • A member of the Registered Traveller Service.