Behind the scenes with controversial pranksters Trollstation

The Head of the Metropolitan Police Federation has warned a group of pranksters they risk being shot by armed officers if they persist with controversial stunts.

The group, called Trollstation, have filmed their antics on the streets of the capital and in tube carriages since 2013.

They have built up a worldwide audience but have been accused of putting themselves at risk and of wasting police resources.

Recently it emerged the group's co-founder is facing a jail sentence for a bomb hoax because of one stunt.

Gareth Furby reports.

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