Students at Cambridge University say they're "appalled and shocked" to discover that police have been attempting to infiltrate and spy on their activities.
An undercover video has emerged of a student being asked by an officer to feed information on politically active campaigns and protest groups.
Cambridgeshire Police says its tactics are within the law, but civil liberty groups say it's an infringement of fundamental rights and covert operations on innocent groups should be banned.
Click below to watch a report from ITV News Anglia's Tanya Mercer
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Rain this evening with showers expected tomorrow and minimum temperatures overnight of 9 deg C 9 66 deg F)
Early fog will clear to leave a dry day with sunny spells and highs of 18 deg C (64 deg F)
Overnight there'll be mist and fog but it will clear for Sunday leaving sunny spells.