Police will step up their presence at a park in response to a series of robberies.

On the evening of September 5, four teenagers were mugged separately at King George Recreation Ground in Bushey, including a 16-year-old boy who had a knife pressed against his face.

They were targeted by men who took their mobiles and demanded their pin codes.

In response to the robberies, police have been carrying out patrols both openly and undercover at the park and have been speaking with park users and nearby residents.

Next weekend, the operation will go further with a knife amnesty.

There will be temporary knife bins between 10am and midday on October 10 and October 11, when unwanted knives can be surrendered anonymously without fear of prosecution.

Watford Observer:

A knife bin in Radlett in the summer as part of a wider Hertfordshire knife amnesty

PC Callum Ellis from the Bushey safer neighbourhood team said: "Whilst detectives from the local crime unit at Borehamwood station have been investigating these crimes, we have been doing all we can to prevent further incidents and reassure the local community.

"This amnesty will provide an opportunity for people to hand over any unwanted knives and remove potentially dangerous weapons from circulation. We will also be speaking to people about the dangers of carrying knives and reinforce the message that carrying a knife is illegal and will not help to keep you safe."

Police continue to appeal for witnesses to the four robberies which took place between 8.45pm and 9.45pm on September 5.

Detective Sergeant Chris Parperi, from the local crime unit, said: "Our enquiries into these incidents continue and I would use this opportunity to renew our appeal for information. One of the offenders was wearing grey clothing and the other three were wearing dark coloured clothing.

"One of the men had a bandana covering his face while another was wearing a surgical face mask. Do you recall seeing these men in the area that evening? If you have any information, please make contact."

Anyone with information can contact police on 101 or visit herts.police.uk/report quoting crime reference 41/71248/20 or contact Crimestoppers anonymously by visiting crimestoppers-uk.org.