It was an image that could have been lifted from a post-apocalyptic movie.
A picture of two robots appearing to square off was widely shared on social media in the past few days. The fact that the two machines faced each other at a pedestrian crossing in Cambridge didn't matter - this was firm evidence that artificial intelligence (AI) had gone too far.
The two-wheeled robots were merely passing each other while performing that most mundane yet vital of tasks: delivering groceries.
Meet the Co-op delivery robots, used by the supermarket giant to bring items across a growing number of areas in the UK.
Yahoo News UK looks at how the robots carry out their job of delivering shopping to customers.
Starship robots: Co-op robot trials expanded to parts of east Leeds (Yorkshire Post)
What are the Co-op robots?
The robots used by the Co-op were developed by Starship Technologies, an Estonian tech company with headquarters in San Francisco that specialises in autonomous delivery vehicles.
How do they work?
The robots are powered by batteries and travel at the same speed as pedestrians. The Co-op says the robots use "a combination of sensors, artificial intelligence and machine learning to travel on pavements and navigate around any obstacles".
They have "computer vision-based navigation" which helps them "map their environment to the nearest inch", the supermarket says. The idea is that the robots are kinder to the environment and reduce traffic congestion.
How do customers order a robot shop?
For a home delivery via robot, customers can download the Starship app and order their groceries, with delivery fees starting from 99p.
The staff at their local Co-op shop will then load the robot and it will travel from the store to the customer's home.
Starship says the average delivery consumes the same amount of energy it takes to boil a kettle to make just one cup of tea. Co-op says the most popular items delivered by their robots are milk, eggs and bread. The robots even have their own names, such as Sir Lance-a-bot, Gizmo and Sunshine.
Where are the Co-op robots being used?
Co-op started trialling the delivery robots in Milton Keynes in 2018 and demand soon intensified during the COVID pandemic. In March 2020, the robot operation expanded into central Milton Keynes, and then later launched in its second UK destination, Northampton.
The robots are now also available in Bedford, Cambourne, Cambridge, Leeds, Rushden, Trafford, Wakefield and Wellingborough.
Starship Technologies told Yahoo News UK that several hundred robots are in use in the UK, serving hundreds of thousands of customers.