An over-heating dog was rescued by Primark staff when it collapsed after being taken for a walk during the heatwave.
A video showed members of the public in Basildon town centre, Essex, rushing to help the pet which fell ill on Monday afternoon in 35C heat.
They lifted the panting dog onto a trolley, borrowed from the nearby Primark, as its legs buckled beneath it.
According to onlookers, the dog was suffering from problems caused by the heat, and its owner said they had taken the dog outside to cool down because their home was hot.
A passerby who filmed the incident and helped the dog, said: "I was walking through the town centre and at first sight, I thought it was someone who had collapsed, but as I got nearer, it became clearer it was a dog.
"I advised the owner to get the underbelly and paws of the dog submerged in cool water and then move her into the nearby metro where it was air-conditioned.
"I was so angry - such arrogance and ignorance! I went into Primark and asked one of the staff if we could get the dog into their door entrance so she could have half a chance of survival.
"With that, the staff member spoke to the manager who was amazing and assisted to get a trolley and load the dog on so the dog could be transported back to the owner's flat."
They added they filmed the incident to highlight how quickly dogs can get to a critical stage.
The member of the public added she had witnessed similar incidents but this was the most severe.
It comes after several dogs and puppies had to be rescued after being left in vans on a ferry on the hottest day ever recorded in the UK.
In total, 10 canines – some of which were Labradors – were transported between France and the UK in the record-breaking 40C heat on Tuesday.
A transportation company responsible for the dogs has apologised for an "error of judgment" after the puppies were found “half dead” after travelling to Dover, Kent.
Soon after the discovery was made, P&O staff got involved in the rescue efforts, taking the least affected puppies up to the dog-friendly zone of the ferry, while the captain spoke to the owner of Daisybrook Kennels.
Of the 10, three were extremely ill due to the heat, although all were taken to the vets as a precaution.
Following an outcry on social media, the owner of Daisybrook Kennels and Transport Services issued an apology.
It was shipping the animals from Germany through France to England when they were found.