Lincolnshire Police has launched an investigation following a minor explosion at the constituency office of gay Conservative MP Nick Boles.

Mr Boles, the MP for Grantham and Stamford, was not in the office at the time of the explosion, which happened shortly before 1.30am on Monday.

A bang and the sound of breaking glass were heard at the junction of North Street and Burghley Street in Bourne, Lincolnshire.

Mr Boles said he understood a home-made device had been thrown through a window.

He said he did not know anything more than that but hoped to learn more “in due course”.

Lincolnshire Police announced a 24-year-old man had been arrested and was helping police with their inquiries.

A police spokesman said: “Police were called to Conservative Hall in Burghley Street, Bourne, at around 1.24am this morning after reports of an explosion.

“Officers attended the scene and minor damage had been caused to the building. No one had been hurt.

“Initial enquiries were carried out and a 24-year-old local man was arrested in connection with the incident. He is currently helping police with their enquires.

“Early indications suggest this incident is not linked to any wider issues or recent events in the county.”

Mr Boles, 47, entered into a civil partnership in May 2011.

He was a candidate in the Conservative primary for the London mayoral election in 2008 but withdrew after being diagnosed with Hodgkins Lymphoma.

He founded the influential think tank Policy Exchange in 2002 with senior Conservatives Michael Gove and Francis Maude.

Mr Boles is currently Parliamentary Under Secretary of State for Planning.