ARMED police are standing guard outside shops across South Yorkshire as a deterrent to would-be robbers.

Vulnerable security firms delivering cash to stores or collecting money have been working with the police to offer an additional deterrent in an operation named 'Monarch'.

Although the force provides a high-priority service to all cash carriers and their employees all year round, this service is intensified over the Christmas period when such robberies traditionally occur.

Police bosses believe that if criminals spot armed presence outside the shops they're planning to rob, they will then abandon their plans.

South Yorkshire Police has warned criminals not all officers carrying out extra patrols over the festive season will be wearing uniforms.

In addition to visiting stores where vans are due to be making deliveries, officers will also follow the vans as they're being driven around, in an other attempt at making criminals think twice about targeting them.

Operation Monarch is running for the fifth consecutive year.

Chief Inspector Caroline Rollitt said: "We'll use a combination of tactics to deter and capture offenders.

"These include deploying both covert and overt police resources, together with specialist firearms teams to keep track on security vans during this vulnerable time.

"The message to criminals is clear - if you intend to commit such offences you will be apprehended and receive a substantial prison sentence."