LONDON, Dec. 22 (Xinhua) -- An army bomb disposal squad carried out a controlled explosion Friday when they detonated materials found by anti-terror cops who swooped on homes in northern England earlier this week.

Media reports quoted unnamed security sources saying police and Britain's interior security agency MI5 had averted a possible Christmas terror attack.

One man arrested on suspicion of terrorism offences in Chesterfield and three males arrested in Sheffield as part of the same operation all remained in police custody Friday night.

Homes in part of market town Chesterfield were evacuated and an area of the town was cordoned off as anti-terror officers searched a number of properties.

As part of the ongoing investigation and search of premises in Chesterfield, an Army Bomb Disposal Unit carried out a controlled explosion at a nearby safe location Friday.

A spokesman for the regional terror police unit in North East England said the controlled explosion took place to safely dispose of material found at the property. A police cordon remains in place around the premises.

National media in London named the man arrested in Chesterfield as the 31-year-old owner of a fish bar in the town. The shop remains sealed off by police.

Counter terrorism detectives have been given until 4 pm on December 25 to charge, release or apply for a further extension to custody of the four men currently being held.