Two teenagers have been sentenced for arson after a fire at the Frogmore Paper Mill site destroyed “irreplaceable” historical artefacts.

The visitor centre at the historic mill in Apsley was "extensively damaged" on January 22, last year, by a fire the boys had started with a lighter which quickly got out of control.

The two 15-year-olds from Hemel Hempstead, who cannot be named for legal reasons, were given 12-month referral orders by St Albans Youth Court yesterday (March 22) after admitting to arson.

Watford Observer: Frogmore Papermill, ApsleyFrogmore Papermill, Apsley (Image: Hertfordshire Constabulary)

A referral order involves meeting with a youth offender panel and taking part in activities aimed at giving back to the community and preventing future offending.

Twelve months is the maximum length that the order can run for.

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

Police investigator Deborah Newsham said: “I hope that any young person who is considering playing with fire sees this case and thinks twice.

“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.”

Watford Observer: Frogmore Papermill itemFrogmore Papermill item (Image: Hertfordshire Constabulary)

Police added that, while no one was injured in the blaze, millions of pounds of damage was caused while "precious" artwork and historic documents were lost.

Apsley Paper Trail Trust CEO Elena Lewendon said: “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.”

Watford Observer: Damage inside Frogmore Papermill, ApsleyDamage inside Frogmore Papermill, Apsley (Image: Hertfordshire Constabulary)

She thanked Herts Fire and Rescue Service, police and the local community, adding that the charity is “determined to rebuild.”

As many as 13 fire engines and police were called to Fourdrinier Way at around 3.30pm and found the mill ablaze, before battling to prevent the fire spreading further through the site.