A TEENAGER who plunged a zombie-style knife so far into the backside of another boy that it had to be surgically removed is to face a retrial.

Aaron Toward-Parker, 18, had pulled the huge blade out from his waistband after a pal had shot another lad with an air pistol during an incident in the Parks in January.

But following a week-long trial at Swindon Crown Court a jury failed to decide whether he intended to cause really serious harm.

After the panel of nine men and three women was discharged by the judge, prosecutors said they would seek a second trial.

Toward-Parker, of Bath Road, pleaded not guilty to wounding with intent to cause grievous bodily harm.

He admitted unlawful wounding, possessing an offensive weapon, and threatening with an offensive weapon - the combat-type knife.

His 17-year-old accomplice admitted unlawful wounding and possessing an imitation firearm with intent to cause fear of violence.

The court heard pair had gone to the recreation ground near Cavendish Square on the evening of Sunday January 20 where the other group was hanging out.

The younger boy, who cannot be named because he is under 18, was due to meet a friend of the victim to discuss texts sent to his girlfriend.

The jury heard the two attackers, one wearing a balaclava, arrived on bikes shortly before 9pm. The masked youth was waving what turned out to be an air pistol.

After finding out which of the group was the one he was there to see, he shot at him with the pellet gun, before telling his accomplice to ‘Back out the shank’.

Toward-Parker pulled the knife out and started waving it about as the victim asked him what he was doing.

The defendant hit him on the head with the hilt of the weapon and the victim claimed his attacker said: "Don’t think I won’t bore you out with the knife." Toward-Parker denies it.

The pair then grappled on the ground. Toward-Parker claimed he had the weapon in his hand when he went to the ground, but it was not there when he got up.

He said he did not know when he lost hold of it and was not aware it had plunged into the lower back of the victim, insisting he had not intended to do it.

Judge Peter Crabtree adjourned the case and remanded him in custody. His co-defendant is also in custody and will be sentenced following the retrial.