BBC staff at Salford Quays are on the picket lines along with thousands of employees across the country.
Some programmes will be disrupted during the 24-hour strike over job cuts.
Around 2,000 posts are set to go under cost-saving plans.
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Greater Manchester Police said "inquiries are ongoing to fully understand the circumstances of the incident."
Business Secretary Greg Clark said talks with Peugeot's boss over a potential Vauxhall takeover were both "constructive and reassuring".
He served in Margaret Thatcher's Cabinet as Home Secretary in 1989 and was also a former Governor of Bermuda.