The man, believed to be aged in his 20s, was found suffering from stab injuries by police at around 3.15pm. Officers found the man after they were called to reports of a stabbing in Beulah Road.
London Ambulance Service also attended and rushed the man to a south London hospital for treatment, where he remains in a critical condition.
A man was arrested near to the scene on suspicion of grievous bodily harm with intent.
The Met’s enquiries into the circumstances remain ongoing.
On Twitter, The Thornton Heath Chronicle has shared pictures of a cordon in place on Beulah Road.
The Chronicle wrote: “Police are investigating a stabbing inside a shop on Beulah Road.
“The road nearest the Beulah Corner Express convenience store has been closed off while police investigate the incident.
“The Air Ambulance landed in Beulah Road Infant School.”
Unconfirmed reports said the man was “stabbed a number of times inside a shop”.
UK News in Pictures posted on Twitter: “Man in a critical after Croydon stabbing.
“A man has been airlifted to hospital after he was stabbed a number of times inside a shop we can reveal.
“Police were called with Paramedics following the attack on Beulah Road in Thornton Heath.”
This latest incident comes after 2021 saw the highest number of teenage murders ever recorded.
New data showed 2021 was the worst year for gun and knife crime in London, with a total number of 30 teens murdered in the Capital.
GB News host Mercy Muroki addressed Mayor of London Sadiq Khan and Commissioner of Police of the Metropolis Cressida Dick for their failure to tackle the issue.
Ms Muroki did not hold back her criticisms on how both have handled gang violence in the capital, claiming that nothing had been done with previously drawn up plans on crime and violence prevention.
Speaking after two teenage boys were killed on December 30 on separate incidents, Ms Muroki said: “As 2021 came to a close many of us up and down the country finished the year on a high note.
“A much high note certainly than we ended 2020 on, but in London, it was a grim end to the year.
“As two boys aged 15 and 16 became the final of 2021 teen stabbing victims.
“2021 is now the bloodiest year on record when it comes to teenage homicides in the capital – which hit 30 for the first time.
She added: “And, though it’s only day 5 of 2022, already detectives in London have launched their first murder investigation of the year as a man was stabbed to death in the capital just yesterday.
“There is nowhere near enough scrutiny on the Mayor of London on this, he is the man with a direct mandate for policing in London, yet his record is abysmal.
“It’s coming up to 5 years since his Knife Crime Strategy was last updated, the Violence Reduction Unit he set up in 2018 has clearly had no impact on knife crime.
“He’s a man without a plan. And as for Dame Cressida Dick, head of the Met Police – she simply needs to get a grip.”
More to follow…