I found this delightful mint on the edge of a shrunken pond in Huyton, L36. The pond was created by local councillors who were trying to establish a wild life area on a formerly grassed plain.
I could find no reference to it in Stace (3rd edition) or in Atlas 2000 and couldn't even enter the species on i Record.
But, I have just moved it over to i naturalist and got a corroboration from an experienced naturalist. To avoid duplication I have now removed it from i Record.
Mentha cervina
Thanks, Gustav, Both i Nat "referees" were English. One of them put me onto an article about this mint. I contacted the author, a Dr. Ambroise Baker, of Teeside University, with the details. From his article there is no doubt examining the flowering stems that is the above. I know my VC Recorder (though I'm not currently in BSBI) and have contacted him in the personal communication facility on i Nat. Regards.
It is a Mediterranean plant with only 2 reported occurrences in the wild in the UK. The RHS think it is native. For reference they are Stoke-on-Trent and Redcar. Check which country your experienced naturalist comes from. The local council are likely to have planted the pond without worrying too much about where the plants came from - to a non-botanist all mints look the same.
If you are certain about the ID get in touch with the Botanical Society of the British Isles (enquiries@bsbi.org) so the recorder for your county can come and check it. Plant records on iNaturalist are unlikely to get into the records as it is very tricky to identify critical species from photographs.