An eyewitness has told ITV Central that a crew is on its way to cut the central reservation to allow cars to turn around.
We have also been told that a coach has arrived to collect stranded motorists who have evacuated their vehicles in the exclusion zone.
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A large tent has been put up around the area while investigations continue.
The kind gesture touched the hearts of many who shared and retweeted words of support for the officer on Twitter.
Two workers were forced into a back office as the robbers tried to force their way into a safe, police say.