Police say they have increased patrols after reports that men have been approaching schoolchildren and asking them to get into cars.

Hertfordshire Constabulary has confirmed incidents have taken place in Croxley Green and Hemel Hempstead over the past week and it prompted numerous schools to write home to parents and warn their children to be vigilant.

Dacorum chief inspector Paul Mitson says he is aware of reports of pupils being approached in the Hemel Hempstead and Kings Langley areas.

He said: “I understand these reports are likely to cause concern in the local community and I would like to reassure people that we are thoroughly investigating the matter to establish the circumstances and have increased patrols in the area.

“I would urge anyone who has witnessed incidents first-hand to please contact us with information so we can get a clearer picture around what has happened and establish whether any offences have occurred.

“Anyone who witnesses suspicious activity of this nature should record the registration number of the vehicle involved and report it to police straightaway.

“If you have information, please contact police via 101.”