Motorists are being warned to stay vigilant after a string of incident where objects were thrown from bridges.

In total 15 incidents have been reported along stretches of the M20 and A228 since January.

Objects ranging in size from gravel and water balloons to bricks and logs have been dropped from crossings between junctions 4 for Leybourne and 5 for Aylesford and Snodland and East Peckham.

The latest incident at 9pm on Thursday, June 4, saw a group of youths throw gravel and small bricks off at footbridge by East Peckham.

Last month stones thrown from a bridge near Teapot Lane, Aylesford, smashed the windscreen of an Audi A6 in two places.

"Throwing anything at a moving vehicle is incredibly stupid and also malicious. It could easily kill someone, especially if they are travelling at high speeds on a major road." — Chf Insp Gill Ellis

No has been injured or arrested following any of the incidents this year.

Following the latest incidents police have erected signs warning offenders of the consequences of their actions, which include lengthy prison sentences and large fines.

In addition Kent Police have put more patrols and extra CCTV in place in an effort to tackle the problem.

Chf Insp Gill Ellis said: "I cannot stress enough how dangerous it is to throw objects from bridges.

"Throwing anything at a moving vehicle is incredibly stupid and also malicious. It could easily kill someone, especially if they are travelling at high speeds on a major road.

"Fortunately reports of this nature are still rare, but those who commit such crimes will face serious repercussions.

"We also want motorists to be aware that incidents such as this are occurring and to remain vigilant."

In July 2010, a 47-year-old man died following a collision involving a lorry and a pick-up truck on the A20 Swanley interchange, after it was reported that stones had been thrown at the lorry.

Chief Insp Ellis added: "We will be monitoring the cameras and will arrest anyone we find carrying out these malicious acts.

"Visible patrols have been increased in vulnerable areas, which will be making regular checks for any suspicious behaviour."

"We are also working in partnership with local schools to inform and educate pupils of the dangers and penalties.

"I would urge parents to also ensure their children know the dangers and consequences of throwing objects onto the highway."