A Metropolitan Police constable today admitted in court to using a derogatory word to describe a black person towards a suspect, but claimed it was not intended as racial abuse.

In an exchange recorded on a mobile phone, Pc Alex MacFarlane, 53, used the word when addressing 21-year-old Mauro Demetrio.

He also said: “Be proud of who you are, don’t hide behind your black skin.”

The conversation took place after Demetrio had been arrested on suspicion of drink or drug-driving and was taken to Forest Gate police station, east London, on August 11 last year.

Southwark Crown Court heard MacFarlane had confessed to saying the word after the suspect recorded him but said it was not intended as a racist insult.

In a police interview read to the court, the defendant said he had used the term after Mr Demetrio had done so first.

Jurors were told the suspect had been arrested after a police radio check discovered he was wanted on suspicion of the use, supply or manufacture of drugs and for failing to attend court.

Giving evidence, MacFarlane, a serving police officer for 18 years, said he remembered Mr Demetrio using abusive language towards the police officers as he was detained in a police van.

“I tried to calm down Mr Demetrio because of his racist abuse towards the police. I challenged him about his language,” he said.

He continued: “I wanted him to understand that the police didn’t deal with him as a black man and that made no difference at all to how the police dealt with him.”

The defendant described Mr Demetrio as giving “relentless abuse” to officers but acknowledged in court that he should not have used the word he did.

“I agree it is a word I would choose not to use,” he said.

The married father-of -two said he was “exhausted” at the time of the incident after working 66 hours between August 6 and 11 following the riots which swept London.

He had also recently been told he may have a form of skin cancer, for which he is still receiving treatment, the court heard.

The trial was previously told Mr Demetrio had become “abusive” to officers after he claimed to have been throttled and pushed up against the window of a police van by another officer following his arrest on suspicion of drink or drug-driving.

He used his mobile phone to record a heated exchange with officers.

The defendant was travelling with seven other officers in a public order unit when Mr Demetrio was stopped on suspicion of drink or drug-driving. No further action was taken for the alleged offence.

MacFarlane denies a charge of racially aggravated intentional harassment, alarm or distress.