Police are reminding people in Northumberland not to let thieves take their bike for a ride.
The reminder follows an increase in the number of bikes being stolen after being left on the ground or against a wall and not securely locked.
Leaving a bike unlocked makes it an easy target for thieves, who see an opportunity to quickly steal the bike and ride away on it.
Northumberland Chief Inspector Peter Reeve said: “Bikes are expensive items - some are worth thousands of pounds - yet people are leaving them either lying on the ground or propped against a wall and not securely locked to a fixed post - they’re even being left insecure overnight.
“Thieves are taking advantage of this, the bikes are easy for them to steal. They can be on the bike and riding away in a matter of seconds, so even if someone is only leaving it for a few moments it can be stolen before they know it.
“It doesn’t take long to lock the bike to a fixed post but will help prevent the bike from being targeted.”
Northumbria Police’s Operation Soundwave aims to target crimes such as bike thefts.
A key part of the campaign is offering crime prevention advice and encouraging people to register valuables on immobilise.com
Ch Insp Reeve added: “Registering items on the immobilise website means if it is lost or stolen and later recovered by police we can identify who the owner is and return the property to them.”