Six fire crews were needed to tackle a blaze that continued through the night.

The Hertfordshire Fire and Rescue Service was called to a derelict house on fire in Sandy Lane, Northwood at 6.49pm yesterday (Thursday, April 20).

A total of 32 fire fighters attended and no-one was hurt or injured.

Watford Observer: Fire crews were called to a derelict house in Sandy Lane, Northwood at 6.49pm yesterday Fire crews were called to a derelict house in Sandy Lane, Northwood at 6.49pm yesterday (Image: Submitted)

Crews from, Watford, Garston, Rickmansworth, St Albans and Hertford attended.  

Additional crews from Redbourn, Hemel, Borehamwood and Welwyn Garden City joined due to the length of the incident.

The fire was not put out fully until 4.53am.

One eyewitness said: “Smoke was billowing over the military quarters on Eastbury Avenue with a significant amount of ash in the air.”

Incident commander Colin Mead commented: "Hertfordshire Fire and Rescue service offer free safe and well visits, this includes not only a safety check but installation of a smoke alarm.

“Book via www.hertfordshire.gov.uk/safeandwell or contact your local fire station."

Hertfordshire Fire and Rescue Service did not say what caused the fire.

The police have launched an appeal for witnesses and information following a suspected arson.