Former Blackburn manager Sam Allardyce has instructed lawyers to initiate proceedings against his Ewood Park successor Steve Kean, Press Association Sport understands.
The action comes in relation to unguarded comments made by Kean about Allardyce to supporters while secretly being filmed.
The four-minute video, apparently filmed during Rovers' pre-season trip to Hong Kong last summer, was released on the internet overnight.
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Frost and fog overnight into Monday. Turning milder this week
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