A university professor has been convicted of scrawling polite graffiti on luxury cars causing thousands of pounds worth of damage.

Stephen Graham, 47, who is a specialist in cities and urban life at Newcastle Universit and is a graduate of Southampton University, today pleaded guilty to the wrecking spree.

He used a screwdriver to scratch words such as ''very silly'', ''really wrong'' and ''arbitrary'' on to vehicles in the Jesmond area of Newcastle.

Graham admitted four counts of damaging cars, at Newcastle Crown Court, and asked for 23 similar offences to be taken into consideration.

At an earlier hearing the value of the damage stood at almost £18,000. The cars included a Mercedes, an Audi, a Volvo and a Mitsubishi.

The spree took place in August last year when residents of Northumberland Gardens woke up to find the polite phrases etched into the paintwork of their cars.

Graham, who lives on a nearby street, was later arrested and charged.

The professor, based at Newcastle University's school of architecture, planning and landscape, previously blamed a bad reaction to alcohol, antibiotics and prescription drugs for his behaviour and said he could not remember what happened.

Julian Smith, defending, said: ''He has no recollection of the course of events that night.''

A graduate of Southampton University, he has previously held lecturing positions at Durham University and the Massachusetts Institute of Technology.

Judge James Gos QC said Graham would be sentenced on February 25 to give time for pre-sentence reports to be conducted.