Police will be armed with powerful machine guns to guard cash deliveries against armed robbers in the run up to Christmas.

Extra firearms officers are to go on duty as police brace themselves for a surge of "cash-in-transit" robberies.

Operation Liaison will see armed patrols follow deliveries to banks, businesses and cash machines across Greater Manchester.

Det Chief Insp Patrick McKelvey, from Greater Manchester Police, said: "Armed officers carrying MP5 machine guns will be waiting for any raiders thinking about targeting cash deliveries."

Police teams on the ground will carry out surveillance on suspected criminals, while the force's helicopter will track them from the sky.

Security firms have bolstered the police efforts by fitting devices to cash boxes and delivery vehicles, which spray thieves with SmartWater - a forensic fluid containing microscopic particles which leave a unique DNA-type code on the offender.

Police say it will allow them to link suspects to crime, even months later.

Speaking at the launch of the operation in Bolton yesterday, Det Chief Insp McKelvey said an increase in the level of violence used against security personnel had strengthened the police's resolve to protect them in carrying out their duties.

"We are hitting these career criminals hard on many fronts that includes on the streets, in the courts and in their communities," he said.

Tim Ramm, Regional Risk Director for G4S Cash Services said: "We work closely with the police to develop training and good practice that will decrease our staff's chances of being victim's of these attacks.

"We also share intelligence that helps deter attacks and catch and convict these violent criminals."