A blaze caused extensive damage at The Crooked House near Dudley, an 18th-century building, on Saturday evening.

Up to 30 firefighters were needed to tackle the blaze at the pub in Himley.

The building was levelled on Monday despite South Staffordshire Council saying it had permitted only the top floor to be demolished for safety reasons.

Its total demolition prompted Dudley North MP Marco Longhi to question why police did not intervene.

Staffordshire Police said in a statement on Wednesday evening: "Our investigation into a fire at the Crooked House on Himley Road last Saturday (5 August) continues as we try to understand the circumstances, which we are now treating as arson.

"This fire has shocked and upset so many given the, albeit not listed, cultural importance and heritage of the building.

"This is not lost on us and a robust investigation using all available information and forensic opportunities is being carried out.

"We have spoken to, and continue to engage, with the owners. However, speculation is extremely unhelpful and could hinder our investigation.

"We're conducting a joint investigation with colleagues at Staffordshire Fire and Rescue Service and are liaising closely with their fire investigators who have confirmed that the cause of the fire cannot currently be determined.

"However, police are following up on a number of lines of enquiry."

They said following an examination by a specialist fire investigator, into the cause of the fire, they "believe the fire may have been started deliberately".

Officers and specialist accelerant detection dogs visited the site on Wednesday to investigate the grounds.