Two teenagers have been given a 12-month referral order after pleading guilty to arson following a devastating fire at Hemel Hempstead's historic Frogmore Paper Mill.

Both boys from Hemel Hempstead, who are both aged 15 and cannot be named for legal reasons, appeared for sentencing on Wednesday at St Albans Youth Court, having pleaded guilty at an earlier hearing.

Firefighters were called to the site in Fourdrinier Way on last January, with the building already well alight when they arrived at the scene.

It was discovered that the blaze had started after the boys used a lighter to start a fire, which quickly got out of control.

Significant damage was caused to the site’s visitor centre, while artwork and documents from the paper mill's past were lost.

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A referral order will see the teenagers meet with a Youth Offender Panel and take part in activities aimed at giving back to the community and preventing future offending.

Herts Advertiser: The site is still closed a year later following extensive damage.The site is still closed a year later following extensive damage. (Image: Herts police)

They were also ordered to each pay £600 in costs and a victim surcharge of £21 each.

Frogmore is the world's oldest mechanical paper mill, but has been closed ever since the fire.

Elena Lewendon, CEO of the Apsley Paper Trail Trust, is determined to get Frogmore up and running again, saying: "We lost heritage that night that can never be replaced.

"Hundreds of artefacts were burnt beyond repair and the mill has now been closed for more than a year.

"It will be a long road ahead for the charity, but we won’t stop our efforts to fundraise so that we can restore and rebuild Frogmore Mill, the oldest mechanised paper mill in the world and an internationally significant heritage site.

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"Despite suffering such a huge loss, we are determined to rebuild and reopen as soon as we can and are now planning a community and environment focused new museum, offering sustainable events and activities for all ages and abilities."

Elena was also keen to thank Herts Fire and Rescue for their work to put out the blaze, and those who brought the teenagers to justice.

"None of this would be possible without the quick response of Herts Fire and Rescue Service on the night of the fire, and the subsequent support of our local community, businesses, friends and families over the last 12 months," she said.

Herts Advertiser: Hundreds of historic artefacts were lost in the fire.Hundreds of historic artefacts were lost in the fire. (Image: Herts police)

"Special thanks to the team of police officers and detectives who worked so hard to make sure those responsible were brought to justice.

"We can now move on and look forward to building a bright, sustainable future for Frogmore."

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"I hope that any young person who is considering playing with fire sees this case and thinks twice," added investigator Deborah Newsham, from the Dacorum Local Crime Unit.

"This incident demonstrates the consequences of reckless behaviour and although I know the boys involved never meant to cause such devastation, they had no thought for what might happen when they started the fire and how quickly the flames would spread.

"The fire, which was battled by dozens of firefighters, destroyed precious artwork and historic documents from the famous papermill, as well as causing millions of pounds worth of damage. Thankfully no one was injured in the fire."