What does grass mean, in term of cooperating with the police? British usage

[question everything]

I am reading The most recent Thursday Murder Club and there are a father and son with blemishes as far as the police is concerned and when asked about some crime they “do not grass.”

Similar to snitch?

[Srkdqltr]

1. Yes snitch.

[question everything]

2. Thanks. I wonder whether they also say snitch...

[Bristlecone]

3. All of the Rumpole books reference the term a time of two each

It means to help the authorities by “ratting out someone”

It’s always a criminal snitching on a criminal in the cases I reference. Often considered going against their “moral code.”

[question everything]

5. Thanks. Consider this book has been a best seller in this country a footnote would have been helpful

[dweller]

4. Never grass

to the peelers …


✌🏻

[bucolic_frolic]

6. Blimey that must be Cockney usage /nt

[Figarosmom]

7. Same as don't lie to me or

Don't fuck me over.

[stopdiggin]

9. no. 'grass' means to inform police/authority

and in my reading and understanding, it remains fairly specific to that.

[Figarosmom]

11. The phrase that I hear on British shows is

Don't grass me up. And it's a cop talking to an informant or in interview rooms.

And I took it for telling them not to lie or mess around wasting their time.

[stopdiggin]

12. I have honestly never heard the term used that way

and in my hearing 'grass' almost invariably means to inform or 'snitch' - or alternatively the informer or snitch.
but if that's the way you heard it - so be it.
language is a moving target. yes?

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[Figarosmom]

13. AI says you are right😊

[Eugene]

8. informant as a "snake in the grass"

And then there's a "supergrass," lower than a snake in the grass,
an informant during The Troubles.

[msongs]

10. sad that doing the right thing is considered bad n