A group of teenagers accused of stabbing a 19-year-old to death dropped a rubber glove in a minicab as they made their getaway, a court heard.

The four youngsters, two aged just 14, allegedly took the cab from an estate in Hendon to Harrow, west London, then asked the driver to wait as they murdered Hussein Ahmed and attacked two 17-year-olds, the Old Bailey heard.

After seven or eight minutes, they returned to the cab and told the driver "Drive, boss", the court heard.

Mr Ahmed was stabbed once in the back in a street near the South Harrow Tube and suffered massive blood loss. He died in hospital three days later.

Another boy was stabbed in the arm and stomach while a third narrowly avoided injury as an attacker slashed the sleeve of his jacket.

The court has heard two of Mr Hussein's alleged attackers were captured on CCTV wearing purple plastic surgical gloves.

Giving evidence from behind a screen and with help from an interpreter, Saifuddin Jaji told jurors how he picked up four youths in his white Toyota Prius on the afternoon of November 18 last year.

They played loud music during the journey to and from Harrow until Mr Jaji told them he had a headache and asked them to turn it off.

Describing their mood in the car at they returned to the Grahame Park Estate, Mr Jaji said: "When they turned off the music they were talking to each other. They were looking very worried."

The court heard how the driver asked for £18 up front to take the fare, and then demanded £24 for the return journey - but the boys were £1 short.

Prosecutor Anthony Orchard QC asked: "When you do a drop off do you check your car?"

The witness replied: "I checked and saw a glove was on the ground in the front side so I took it. It was a rubber glove."

He added: "I threw it away - I did not suspect anything."

The Embassy Cars driver told jurors he made a U-turn after dropping the boys off and took on two more fares that day.

When police contacted him the same evening, Mr Jaji said they told him "these boys stabbed someone", but before then he had no suspicions that anything was wrong.

Two 14-year-olds and a 16-year-old, who cannot be named for legal reasons, deny murder, wounding with intent, attempted wounding with intent and conspiracy to cause grievous bodily harm.

A fourth boy aged 16 fled the country and is wanted by police, the court heard.