He suggested that workers should not have to do their jobs if temperatures rose to above 30C.
It would be even better for physical workers, on building sites for example, where the limit would be just 27C.
Mr. Corbyn failed to get the law passed at the time, with only 36 MPs agreeing to it but the Mirror reports that he still stands by the policy.
At the time he said:
In this weather, high temperatures aren't just a problem in heavy industry but for millions of workers have been struggling with the heat in offices, schools, shops, call-centres - you name it.
Good employers will have been taking steps to help out their workers in the heatwave.
But putting a maximum temperature into law will give everyone a legal right to basic protections from working in unbearable conditions.
So this begs the question the question:
Could we go home today, June 19th 2017, if Labour had won the general election?
We're sorry to say - only some of us.
Builders and other physical workers would be rejoicing across England and Wales as temperatures are currently exceeding 27C but the rest of us will have to sweat it out as temperatures are only reaching 29C at the time of writing.
Sadly Scotland and Northern Ireland wouldn't be so lucky as it is considerable cooler there, peaking at a chilled 22C.
Still, with things only likely to get hotter in the coming months perhaps Jeremy should be promoting the issue again.
He might win round a few voters by promising them a day off in the sun.