A Taser stun gun has been used by police officers on a woman wielding a knife and threatening to injure others and herself at a function in a club.
Taser guns fire needle-tipped darts up to 21ft to disable suspects
Police were called to the Caribbean Club on Woodbridge Road on Friday night and cleared the function room where the woman was brandishing the knife.
After negotiations failed the Taser weapon was used on her and she was later taken to Ipswich Hospital.
She was found to be uninjured and was then detained under mental health laws.
A police spokesman said that it was their standard procedure when a Taser weapon was used to notify the police professional and ethical standards office.
They said no further comment on the incident would be made.
Doug Jewel from the Human rights group Liberty has raised concerns about the use of the stun gun and said the weapon can be lethal if someone has a medical condition.
"They are very dangerous weapons and people have been known to have been killed.
"A lot of information is coming from the United States where very serious consequences such as deaths have been reported.
"Police have to be aware of this before using this weapon," he said.
Controversial Taser electric stun guns are to be carried by trained police firearms officers in Suffolk.
The weapons work by giving out electric charges to disable people acting in a threatening way.
The guns fire a pair of barbed probes into the clothes or skin of a target to create a circuit which allows 50,000 volts of electricity to flow.