Alex Pearce was doing the morning rounds at his fruit and vegetable wholesale business in London on Monday last week when he noticed something odd.

The defrost light on refrigeration unit 2 was on, and the panel reading was 150C. Unit 4 was the same.

As he approached his biggest unit, its defrost light also blinked on.

It was at this point that Pearce thought: is this a cyber-attack? He walked over to the box connecting the units to the internet and yanked out the cable.

He was right.

Alex Pearce unplugged the internet at his wholesale fruit and vegetable business after seeing the temperature of the refrigeration units shoot up.…