Eleven-week-old Teddie Mitchell was described as a “totally broken baby” with injuries “akin to Baby P” in the harrowing first part of 24 Hours in Police Custody last night (January 3).

The one-hour episode on Channel 4 started with a shot of mother Lucci Smith sitting in her police cell saying she had “always wanted to be a mum”.

Then footage switched to the 999-call made from her flat, at Love's Farm, in St Neots, shared with partner Kane Mitchell, on November 1.

Viewers hear CPR being carried out on baby Teddie before a pulse is regained at 15.44pm at Hinchingbrooke Hospital.

Police are present due to Teddie suffering a cardiac arrest, although no child protection background with the family is established.

Detective Inspector Lucy Thomson says cases such as these are “the hardest to investigate”.

“You are dealing with the most vulnerable people in society [babies] who rely on adults around them to protect them,” she explains.

At the hospital, Mitchell walks in and says “daddy is here” although it is later established, he is not Teddie's biological father.

Medics say Teddie is not responding to treatment and police are told he has a fractured skull and a major bleed to the brain - described as "catastrophic" and "unsurvivable".

Mitchell has an outburst of foul language when told he is under arrest alongside Smith in the hospital. He is told by a doctor to calm down as there are sick children in the hospital.

As the investigation continues, the pair are interviewed and Smith says she thought Teddie was “just tired” and “really poorly” so decided to phone a doctor.

In floods of tears, Mitchell says Teddie was “white as a ghost and cold to the touch.” When talking about the CPR while on the 999-call, he says “it wasn’t working, I knew he was dying”.

Smith says that the head injury could have been sustained from when he “headbutted her five-year-old".

At the flat, police find a home environment that doesn’t look “neglectful”, so they start to look more at the dynamics of the relationship.

Outside, one of the neighbour's alerts police to concerns over Mitchell's aggression. But in custody, he insists the relationship is “solid” and "the best he’s ever had”.

When released on bail the couple keep vigil at Teddie’s bedside until they decide that his life support machine should be switched off.

Footage from a neighbour is shared with police of one of Mitchell’s violent outbursts. Police say it is “chilling” as Mitchell can be heard screaming “hurry up” and loud thuds come from the flat.

Police vow to continue to investigate as a sombre "R.I.P. Teddie" is said at their meeting. It is clear the effects the case has had on them too.

It is thought that during the 20 minutes when Smith took her other children to school, that is when Mitchell injured Teddie.

Police interview a former girlfriend of Mitchell, who says he would “just flip”.

“In that relationship there was nothing left of me,” she explains.

“He [Mitchell] would strangle me, spit in my face and call me names.”

Violent text messages are also discovered sent from Mitchell’s phone to Smith when she decided to take her children to the park after school one day.

Post mortem results find that Teddie has broken ribs, spine, both clavicles, skull and pelvis.

One detective says “this is akin to Baby P-type injuries.”

Teddie is described as a “totally broken baby”.

DI Lucy Thomson adds: “I have never investigated a job with that level of injuries to a baby. It was a combination of months of sustained ill treatment.”

24 Hours in Police Custody: Cold to the Touch continues on Channel 4 at 9pm tonight (Tuesday, January 4).

Mitchell was jailed for a minimum 18-year term at Cambridge Crown Court in February.

Smith was convicted of cruelty to a child. The trial heard she did not dial 999 for more than 30 minutes after being urged to do so.