The government's preferred route for the HS2 rail extension passes close to a number of natural beauty spots north of Birmingham including Shugborough Hall and the village of Great Haywood.
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The announcement came a day after a famine was declared in two areas of South Sudan following three years of civil war and severe inflation.
It is unclear what their alleged plans were.
Anti-terror police are currently questioning the men who were arrested at three separate locations in France.