A 28-year-old man has admitted to starting a fire that destroyed the constituency office of Labour MP Sharon Hodgson.

Joshua Oliver, of no fixed address, pleaded guilty to arson, with the resulting fire wrecking the Washington and Gateshead South MP’s office in the early hours of Thursday.

The guilty plea was entered at Newcastle magistrates court on the basis that it was reckless rather than intentional. The crown did not accept the basis of the plea.

The fire gutted the premises, as well as those of a small charity for people with very rare genetic diseases called Niemann-Pick UK (NPUK). An NHS mental health service for veterans was based in the same building.

Fire investigators were seen on Thursday at the offices in the Concord area of Washington, Tyne and Wear. Graffiti on the side of the building reads “328 days blood on your hands,” although it is believed to have been there for as long as a year.

Oliver had been living in a tent nearby, the court heard. District judge Kate Meek remanded him in custody to appear at Newcastle crown court on 14 October.

Oliver was charged with arson of Vermont House, Washington, with the damage estimated at between £250,000 to £500,000, and he admitted starting a fire in a wheelie bin that then spread.

Heather Bolton, defending, said: “He accepts he has set fire to the wheelie bin, he didn’t intend for the fire to spread to the building.”

The defendant was told a decision will be made whether a Newton hearing, which would rule whether the offence was intentional or not, will be necessary.

Oliver also admitted burgling the building when he stole a mallet and power tools on the night. He admitted three counts of criminal damage, namely smashing windows at Vermont House, in the days before the fire.

The defendant also admitted twice smashing windows at his father’s house in Sunderland in July.

The district judge said he will be sentenced for all offences at the crown court.