The death of a Conservative MP in Essex is now being treated as a terrorist incident.

Sir David Amess, MP for Southend West, was stabbed whilst holding a surgery event at Belfairs Methodist Church in Leigh-on-Sea on Friday.

A 25-year-old man arrested at the scene on suspicion of murder is in custody at an Essex police station.

East Anglian Daily Times: Sir David Amess with his pugs, Lily and Boat at the Westminster Dog of the Year competition at Victoria Tower Gardens in LondonSir David Amess with his pugs, Lily and Boat at the Westminster Dog of the Year competition at Victoria Tower Gardens in London (Image: PA Wire/PA Images)

Senior National Coordinator for Counter Terrorism Policing, Deputy Assistant Commissioner Dean Haydon, has now formally declared the incident as terrorism.

Early investigations into the MP's death revealed “a potential motivation linked to Islamist extremism”, the force said.

As part of the investigation, officers are currently carrying out searches at two addresses in the London area, the Metropolitan Police said.

The force believe the man acted alone and are not seeking anyone else in connection with the matter at this time but inquiries into the circumstances of the incident are continuing.

The investigation is being led by the Met’s Counter Terrorism Command who are working with the Eastern Region Specialist Operations Unit (ERSOU) and Essex Police, the Met said.

It said formal identification is yet to take place, but the victim has been identified as Sir David Amess and specialist officers are supporting his family.

Witnesses, or anyone with information about the incident are urged to contact police.