A reporter for Chard and Ilminster News has tweeted this photo purporting to show the closed service station at Southfield roundabout.
A large heavy goods vehicle can be seen in the background surrounded by police and ambulances.
The scene at Southfields Roundabout services. Police cordoned off a HGV. Appears to be around 20 people inside it. http://t.co/aUTBj5wVHG
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Armed police have carried out a raid apparently linked to Wednesday's deadly terror attack in Westminster.
Cheryl Grimmer vanished from inside a beach shower block in Wollongong, Australia, in 1970, when she was just three.
Pc Keith Palmer was on the front line and because of his actions, the Westminster attacker was unable to kill anyone else.