TV watchdog Ofcom has launched an investigation into Top Gear presenter Jeremy Clarkson's comments about striking public sector workers.
The host was forced to apologise after saying all striking workers "should be shot".
The comments - made during The One Show on November 30 - led to more than 21,000 complaints to the BBC and almost 800 to Ofcom.
Ofcom is investigating the comments under broadcasting rules on "generally accepted standards".
"Ofcom has taken the decision to investigate comments made by Jeremy Clarkson on BBC1's The One Show," it said.
"We will make the outcome of the investigation known in due course."
The TV regulator is also investigating other comments Clarkson made on The One Show describing people who kill themselves at railway stations as causing "immense" disruption to commuters.
The remarks about strikers led to condemnation by union leaders and politicians, with Prime Minister David Cameron branding Clarkson's comments "silly".
His gaffe came as he appeared on the BBC1 show on the evening of Britain's biggest public sector strikes for 30 years.
Speaking about the strikers, he said: "I'd have them all shot. I would take them outside and execute them in front of their families.
"I mean, how dare they go on strike when they've got these gilt-edged pensions that are going to be guaranteed while the rest of us have to work for a living?"
Clarkson later said in a statement that his comments were not meant to have been taken seriously.
"I didn't for a moment intend these remarks to be taken seriously - as I believe is clear if they're seen in context," he said.
"If the BBC and I have caused any offence, I'm quite happy to apologise for it alongside them."
But in a later interview he appeared to be taking the matter less seriously, when he also apologised to sparrows, after saying he did not like them during The One Show.
The BBC said the item "wasn't perfectly judged".
Earlier this year the BBC apologised about an item on BBC2's Top Gear which led to the Mexican ambassador complaining about the "outrageous, vulgar and inexcusable insults" made about Mexicans by Clarkson and co-hosts James May and Richard Hammond.
The BBC's editorial complaints unit upheld criticisms of the show and ruled that it reinforced stereotypes.
In February 2009, Clarkson famously called then-prime minister Gordon Brown a "one-eyed Scottish idiot" and in November the previous year, the BBC received almost 2,000 complaints when he joked about lorry drivers murdering prostitutes.
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