A 28-year-old man has admitted setting a fire that caused significant damage to a building containing the constituency office of Labour MP Sharon Hodgson.

Joshua Oliver, of no fixed abode, pleaded guilty at Newcastle Magistrates' Court to arson and burglary after a blaze broke out just after midnight on Thursday at Vermont House in the Concord area of Washington, near Sunderland.

The courtroom heard the fire destroyed the front of the building and damaged offices used by a small charity supporting people with very rare genetic diseases and an NHS mental health service for veterans. Sharon Hodgson is one of several tenants based at Vermont House; she represents Washington and Gateshead South.

Magistrates remanded Oliver in custody ahead of his sentence at Newcastle Crown Court on 14 October. In addition to the arson and burglary pleas, Oliver admitted stealing a power tool on 10 September and a number of criminal damage offences committed between July and September, the court was told.

The defence said Oliver accepted the arson charge on the basis that the fire was reckless rather than intentional. The Crown Prosecution Service did not accept that basis of plea, a point that is expected to be considered further at the crown court hearing.

Court documents indicated that Oliver had been living in a tent near the building prior to the incident. Police and fire investigators attended Vermont House after the alarm was raised in the early hours; emergency services worked to extinguish the blaze and to assess the extent of structural and internal damage.

Authorities have not made any public finding that the attack was politically motivated. No one was reported to have been injured in the incident. The damage has disrupted services for the charity and the veteran mental health provision that shared the premises with constituency offices.

Sentencing at Newcastle Crown Court will determine Oliver's punishment and will also provide an opportunity for the prosecution to set out its position on whether the arson was deliberate or reckless. Police enquiries and any related investigations into the series of offences admitted by Oliver are ongoing.