The murder of the UK Conservative MP Sir David Amess on Friday is being treated as a 'terrorist incident', police have confirmed.
The Catholic MP, who had represented Southend West since 1997, was stabbed to death inside Belfairs Methodist Church in Leigh-on-Sea as he met constituents.
A 25-year-old man was arrested at the scene on suspicion of murder. The man, understood to be a Briton with Somali heritage, remains in custody at an Essex police station.
The Met said investigators were pursuing "a potential motivation linked to Islamist extremism".
Two properties in London have been searched by police as part of investigations.
Sir David spent nearly 40 years as an MP, having been first elected in 1983.
He was a committed Catholic who helped to arrange Pope Benedict's visit to Parliament in 2010, and was involved in the pro-life movement, serving as a patron of the pro-life charity Right To Life UK.
Politicians and Church leaders have both spoken of their "profound sorrow" over his death.