A joint investigation has been launched by Hampshire Constablary and Hampshire Fire and rescue arson task force. The probe comes after a blaze has ripped through a historic fort in Gosport.
Firefighters from across the Hampshire have been mobilsed to tackle the blaze that has ripped through abandoned property.
Flames have broken through to the roof and can been seen from Lee on the Solent seafront.
Fire crews are likely to remain tackling the blaze.
A spokesman for the fire service said that they were called at 5.17pm to reports of a fire.
Thirty firefighters four appliances and a water carrier are at the scene.
A spokesman for Hampshire Constabulary said: ‘We were called at 5.26pm on Sto a report of a fire at a disused wooden shed at Fort Gilkicker in Gosport.
‘Officers and colleagues from Hampshire Fire and Rescue Service attended.
‘The shed was completely burnt out.
‘The incident is being treated as arson.’
Anyone with information should call police on 101, quoting crime reference number 44190092488.