Two teenagers involved in a knifepoint robbery in Cassiobury Park have been given supervision orders.

Rhys Bannister, 18, was enjoying himself in the Watford park with friends when a 16-year-old from another group of youths began throwing stones at them.

The 16-year-old, who cannot be named for legal reasons, believed wrongly that Mr Bannister had attacked him previously, St Albans crown court heard Wednesday.

Prosecutor Michael Speak said the 16-year-old shouted abuse and he and others then surrounded Mr Bannister, who took his mobile phone out to call the police.

The 16-year-old threw a punch at a friend of Mr Bannister’s who intervened, but missed.

He then got Mr Bannister in a headlock and they both ended up on the ground.

He urged others from his group to assault Mr Bannister and a 17-year-old youth kicked him.

The 16-year-old produced a small knife and held it towards the victim's chest telling him to "drop his things" before fleeing with his mobile phone and Ipod.

The attackers were identified by CCTV taken from Watford town centre, where they had been earlier in the afternoon of Monday, April 6.

In interview the 16-year-old said he mistook Mr Bannister for someone who had attacked him earlier.

He claimed to have hidden the mobile phone and Ipod in a safe place, but when he returned to get them they had disappeared.

The 16-year-old pleaded guilty to robbery and the 17-year-old admitted causing actual bodily harm. It happened on April 6 this year.

The 16-year-old had reprimands for causing criminal damage and battery when he was aged 13 but his older accomplice was of previous good character.

Andrew Kerry, defending the 16-year-old, said he was “remorseful” and fully accepted what he had done when he was arrested.

David Batcup, for the 17-year-old, said he had been living in a hostel in Watford but was now supported by his family and was due to start a job in Borehamwood.

Judge John Plumstead told the 16-year-old he was taking an exceptional course in not sending him straight to custody.

He passed a two-year intensive supervision order which means the youth will have to report back to the judge every three months, starting December.

He must also abide by a curfew between 7pm and 3am for three months.

He urged the youth to make a face-to-face apology to Mr Bannister, if the victim wished to see him.

He told him: "If you betray me by re-offending you will go straight to custody. This is a single chance. Behave yourself or go inside."

The judge gave the 17-year-old two years supervision describing the attack as "shameful”.