The attack happened at about 8.30pm on Saturday (July 19) when a 33-year-old woman walking home from the train station was grabbed by a man at the junction of Station Road and Heath Lane.

The attacker, who had been following the woman, put his arm around her neck and tried to drag her into the undergrowth of a nearby field.

He was only stopped when brave passing motorists saw what was happening and pulled over to shout at the man.

The offender then fled down Station Road and across the field, possibly towards Boxmoor Cricket Club or the Three Blackbirds Pub in St John's Road.

Police said the woman was left 'very shaken but unhurt' and that a knife was later recovered from the scene.

Yesterday (Wednesday), after a police appeal for witnesses was published in our sister paper The Gazette, a 30-year-old woman from Hemel Hempstead came forward with information about a suspicious incident in Boxmoor.

The woman, who asked not to be named, said she saw a man turn and follow a woman as she entered the moor off London Road on Thursday (July 17) – just two days before Saturday's attack.

She said: "It was about 1.15pm and I was driving home from work.

"I saw a girl walking onto the moor through the metal gate opposite the Harvester restaurant.

"A Chinese-looking man walked past but then he turned back and followed the girl through the gate and walked very close behind her.

"At the time it just didn't seem quite right."

The woman, who described the man she saw as about 5ft 8 or 9ins tall, skinny and wearing dark clothing, said she was going to get in touch with the police.

The man suspected of Saturday's attack was described by Herts Police as an 'Eastern European-looking' man in his mid-twenties about five ft 10 ins tall, of medium build, with olive skin and jet-black hair.

He was wearing blue jeans with a blue T-shirt and was carrying a distinctive rucksack with an orange pattern on it.

Anyone with information about the incident is asked to call 0845 3300222.