Jeremy Clarkson should be sacked from the BBC, Sherlock star Mark Gatiss has tweeted.

Let's back up a bit. Jeremy Clarkson is a presenter on the tv program "Top Gear," where they talk about cars, kind of. "Top Gear" has a long history of pushing the grey area between national humor, or making fun of other countries, and racial humor, or making fun of, well, you get it. They have gotten in trouble for crossing this boundry before.

Recently Ofcom decided that remarks Clarkson made during the show's Christmas special were rascist.

The Ofcom ruling relates to a scene where Clarkson was looking out over a makeshift bridge across Thailand's River Kwai. He said: "That is a proud moment, but there's a slope on it" as an Asian man walked towards him. Co-presenter Richard Hammond, 44, replied: "You're right, it's definitely higher on that side."

In its ruling Ofcom said: "Jeremy Clarkson deliberately employed the offensive word to refer to the Asian person crossing the bridge as well as the camber of the bridge." Ofcom pointed out that the sequence had been scripted in advance and the production team would have known of the intended use of the offensive word.

Doctor Who screenwriter Gatiss, 47, suggested the Top Gear presenter will "have to go" following Ofcom's ruling that Clarkson's "slope" comment was offensive. Gatiss is the first BBC star to publicly hint 54-year-old Clarkson should lose his job.

"So Clarkson was given one last chance, yes? So now he'll have to go, yes?" Gatiss told his 530,000+ Twitter followers.

Ofcom's ruling comes just months after Clarkson was given a final warning about his behaviour by the BBC. Clarkson had been forced to apologise for using the word n***er during un-aired Top Gear footage obtained by the Mirror.

 Lawrence Davies, a solicitor for Equal Justice, said: "Clarkson is a serial offender. He is already on a final written warning and must be immediately disciplined. The BBC promised the British public that they would take decisive action if Clarkson re-offended. They now have a chance to take a stand against racism and I hope they take it."

Indian-born actress Somi Guha, who complained to Ofcom about Clarkson's Asian slur, said: "I feel vindicated by the Ofcom decision.

"I hope that the BBC meant the final written warning they issued against him for the n-word mumbling and that it was not just a gesture on their part. If they meant it, they should dismiss him now."

A BBC spokeswoman said: "We dealt with this matter some time ago.

"The programme apologised at the time and explained the context and we are now focusing on delivering another series of one of Britain's best-loved shows."

The BBC claimed in April it was "not aware" the ethnic slur "is considered by some to be offensive," insisting the use of the word was merely "a light-hearted word play joke".

Clarkson was accused of racism after mocking Indian culture in a Top Gear Christmas Special. And in footage from out-takes of the show, Clarkson can be heard reciting a racist version of a children's counting rhyme.

He swung his finger between two cars, chanting: "Eeny, meeny, miny, mo..." before muttering: "Catch a n***er by his toe".

He later begged forgiveness from viewers, saying his attempt to obscure the n-word "weren't quite good enough".

More updates as they become available.