Safer Neighbourhood Teams will be security marking bicycles for free today.
Officers in Shenley and Potters Bar will be security marking bicycles in Shenley’s Harris Lane playing fields from 3pm to 4pm, along with Potters Bar high street from 11am to midday and the Furzefield skate park from 1pm to 2pm.
As well as marking the bikes, officers will also be offering crime prevention advice and handing out cycle secure leaflets.
All bicycles marked during the day will also be entered onto the police's Immobilise database.
PCSO Cheryll Lavell said: “Security marking your bike makes it safer as it not only helps police to reunite lost or stolen items with the owners, but also acts as a deterrent to thieves. If we catch a thief with a bike which has been security marked we can quickly establish that a crime has been committed and make an arrest.
"Bikes that are clearly security marked are less attractive to criminals.”