An argument about dirty windows at an Oxford city centre shop erupted into violence when a cleaning firm manager punched his colleague on the nose.

The row at D. F. Williams Cleaning Services, of Magdalen Road, Oxford, was sparked by a complaint from a customer - the Sports and Soccer shop in the Westgate Centre - about the cleanliness of its windows.

Cleaning manager Dean Giles admitted walking into contracts manager Timothy Crysell's office and punching him on the nose.

But he denies causing actual bodily harm, claiming it was in self-defence.

Oxford Crown Court was told Mr Crysell needed hospital treatment following the attack on November 3 last year.

He also suffered headaches, vomiting and became afraid of bright light. A large abscess which developed in his nose needed an operation. The court heard Mr Crysell may have nose deformities in later life.

Alan Blake, prosecuting, claimed 40-year-old Mr Crysell was the victim of an unprovoked attack.

Mr Crysell said he was sitting at his desk when Giles, 40, of Paradise Square, Oxford, entered the office.

Mr Crysell said Giles walked towards him, swearing and accusing him of causing the problem with the Sports and Soccer shop.

Mr Crysell said: "He was agitated and very aggressive."

Giles stood in front of Mr Crysell, who rose from his chair. However, he was punched in the nose before he could stand up.

Giles immediately claimed the blow was in self-defence.

Mr Crysell said: "I couldn't believe what I was hearing. I wasn't acting in any way threatening.

"I still don't understand why he hit me."

Tony McGeorge, defending, said Mr Crysell had verbally abused Giles earlier that day about the complaint and Giles had a legitimate reason to fear an attack from him.

Giles said: "When I came into the office, Tim was staring at me.

"He was very, very angry. I thought he was going to attack me.

"I never had any premeditation to hit him. It was just a reaction."

Tanya Smith and Patrick Mcevoy, who also worked in the office, said Giles was acting aggressively and Mr Crysell's arms were held out in a placatory way when he rose from his chair.

The case continues.