Super Grass - meaning?

[Steffiy]

What is a super grass? There is someone on the news who is a super grass - are they a spy?

Thanks

:)

[Quizmonster]

A grass is an informer, so a super-grass is an especially important one who is going to provide the police or the court with lots of vital information.

[Big Al1st]

As quizmonster says they are super informers who usually get off with the crime or get a much reduced sentence. However it can cost tax payers alot of money as they usually end up in a witness protection system which involves setting them up with a complete new life.

This happened alot during the Irish troubles.

If you are thinking about the Muslim sent from America testifying in London. Not sure why he is doing this as he shows no remorse and apparently is going to get a hefty jail sentence himself.