Suffolk police are treating a fire which destroyed the listed building at the former Fisons factory near Ipswich as arson.

Fire crews were called to the former Fisons factory in Bramford in the early hours of Monday morning.

They arrived to find the listed north warehouse part of the building well alight.

Officers spent a number of hours on the scene, dealing with the blaze.

Suffolk Fire and Rescue Service group commander Ian Mallet said on Monday that the cause was believed to be "of suspicious origin".

READ MORE: Huge inferno at former Fisons factory may be arson, say fire chiefs

Suffolk police have now confirmed that they are investigating the cause of the blaze.

A spokesman for Suffolk police said: "Police are treating the fire as an incident of arson and investigations are being carried out."

Officers have also been working with staff from Historic England on the case.

A spokesman for Historic England said: "We are familiar with the Fisons building and were sad to hear of the damage caused by the recent fire.

"We have been in contact with the Heritage Crime Liaison Officer for Suffolk police to advise on the investigation into how the fire began.

"Colleagues in our East of England local team have also been in contact with the local planning authority, Mid Suffolk District Council, offering support following the fire.

"We will continue to offer advice and support on the next steps for the building."

READ MORE: 'Preservation of life comes first' - Fire chief explains how Fisons fire was tackled

Any witnesses to the incident should call Suffolk police on 101 quoting crime number 37/255/39/19.

The site's developers, Paper Mill Lane Properties, have been contacted for comment.

READ MORE: Developers quizzed over security measure taken at former Fisons site