Tragic murder of Sian O'Callaghan as Martin Freeman ITV drama about her disappearance hits Netflix

An ITV drama from Martin Freeman has appeared on Netflix in which viewers revisit the tragic murder of Sian O'Callaghan.

Sian was killed in 2011 but initially disappeared after a night in Swindon.

She went missing on March 19th and her body was found on March 24th.

The drama follows Freeman as Detective Steve Fulcher, the real man who led the investigation into Sian's disappearance.

The drama, called A confessionsees Fulcher leading the search for the young woman, who was just 22 years old at the time of her death.

Amazingly, in the show – and in the real case – not only the murder of Sian, but also another woman was revealed.

When Fulcher managed to extract a confession from taxi driver Christopher Halliwell and took him to where he hid Sian's body, he was taken to a location in Eastleigh, Gloucestershire, where he showed detectives the body of the missing Becky Godden-Edwards.

Becky was a young sex worker who tragically died and had been missing for around eight years.

When discussing the role of Fulcher, Martin Freeman focused on one of his controversial choices.

When Fulcher found Halliwell, he did not read him his rights, provide him with a lawyer, or take him to the police station, but instead used emergency powers to force him to admit to the murders.

He said he wanted to speak to him “man to man” because he believed there was an imminent threat to his life.

Freeman said: “His whole argument is that someone could still be alive if you don't know they are dead.”

Martin Freeman plays the real detective (ITV)

“Even if the probability percentage continues to decrease as the days go by. And I totally respect that.

“The question he always asks is, if it was your son or daughter, what would you expect people to do? I have no answer to that other than what he did.

“He didn’t take Christopher Halliwell into a room and kick him. He didn't trick him. He didn't put any words into his mouth.

“If no one told a civilian that these rules were violated, we would never know why they were violated. Because it looks sensible.”

When researching the role, Freeman said: “He struck me as very professional, had very high standards and was in no way a pushover. And probably even someone who could drive you crazy.

Christopher Halliwell is serving a life sentence (PA/Handout)

“I don't think he would ever say, 'It'll be okay, that's enough.' He struck me as someone who would ironically say, 'This is being done the right way,' given that his decisions violated PACE.”

Fulcher's decisions breached the Police and Crime Evidence Act (PACE), although they were still able to secure Halliwell's conviction.

The case marked the end of his career due to his violation of PACE.

Halliwell was convicted of the murder of Sian O'Callaghan in 2012 and sentenced to life in prison.

While Halliwell was not initially charged with Becky Godden's murder, he was later found guilty and given a life sentence – meaning he is ineligible for parole and will likely die in prison.