Police have arrested a man on suspicion of stalking after an 11-year-old girl was followed and then touched in a busy street.

The girl was on her way to school when she was approached in Vicarage Road, between the football ground and Watford General Hospital, police said.

It happened yesterday (Wednesday) between 8.30am and 8.40am.

Hertfordshire Constabulary says a man reportedly tried to speak to the girl before touching her shoulder.

Passers-by saw what was happening and intervened.

They made sure the girl arrived at school safely, where her parents were later contacted and police informed.

Police launched an investigation and this morning, a man from Watford was arrested.

Watford chief inspector Matt Phillips has stressed this incident is an "isolated case".

He said: "I completely understand that news of this is going to cause deep concern within the community but thanks to the quick actions of the public, the victim’s school and the police, a man is currently in custody.

"Detectives are supporting the victim and her family, and several lines of enquiry are currently underway.

"Incidents of this nature are very rare in Watford and Hertfordshire as a whole, and I can confirm that we are treating this as an isolated case.

"In light of yesterday’s incident I would encourage parents and carers to discuss personal safety with their children and ensure they know that it is appropriate to dial 999 if they believe they are being followed by a stranger.

"If you witnessed what happened and have not yet spoken to police, please contact us quoting reference ISR 163 of 26 February."