SPECIAL "Christmas" lights switched on in Darlington will deliver nasty shocks to criminals all year round.

All suspects taken to the main police station will in future be routinely scanned by two ultra-violet strip lights searching for tell-tale signs of "Smart Water", a new chemical security aid.

The water, invisible to the naked eye, can be bought to mark any item of personal property, from car engines to laptops, mobile phones and even jewellery.

Sprays firing out tiny droplets of the liquid can also be added to security systems in commercial premises.

"Anyone who has been in contact with any covert spray or security-marked object will light up like a Christmas tree under the strip lights," said PC Steve Rich, Darlington's crime prevention officer.

"The fine droplets released into the air by security sprays will stay on the hair, skin and clothing for months.

"Each batch of water is unique and based on a similar system to DNA. A minute particle from a suspect will tie them into a burglary or item of stolen property."

As well as fitting the strip lights to the custody area, a smaller unit will also be used in the station's property store to scan all items recovered by police.

Luminous green stencils have been painted on to the walls and ceilings of the cell-block to reinforce the message to criminals. Patrol officers will also have portable ultra-violet lights to do spot-checks on the streets.

Officers plan to write to 500 commercial premises in Darlington explaining the system and that local police now have the infrastructure to deal with it.

The Smart Water, being sold by Electronic Security Solutions, which maintains the CCTV system in Darlington, is available to any member of the public requesting it.

"Each application has its own unique characteristics and providing it is registered with the manufacturer's database, we can identify any marked stolen property we recover," said PC Rich.

"We will also be able to link intruders to properties fitted with the sprays and which have been illegally entered.

"Police searches of suspects' homes will, in future, be subject to sweeps with the portable equipment."