The Independent Police Complaints Commission has announced it is launching a formal investigation into the arrest of a man in Nottingham, who was shot with a taser stun gun three times.
A spokesman for the IPCC said they had now viewed the material and decided it warranted a fully independent investigation.
IPCC Commissioner Amerdeep Somal said: "Footage of this incident, which many people will now have seen, is of sufficient concern to merit a fully independent investigation.
"We would urge anyone who was present and witnessed this incident at any stage, from outside the nightclub to where the man was restrained, to tell us what they saw.
"We will want to look at any relevant CCTV footage of the incident as a whole as part of our thorough investigation.
"At the conclusion of our investigation we will make our findings public."
The Independent Police Complaints Commission will seek to establish whether the force used by police during the arrest was proportionate to the threat they faced.
There are strict guidelines for the use of taser stun guns, which carry a shock of up to 50,000 volts. Several people have died in taser shootings in other countries in recent years.
The Home Office recently announced that a further 6,000 taser guns would be distributed among police forces in England and Wales after a successful 12-month trial of the weapon.
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