Along with a tryptamine clause which AMT is exempt due to the substitution not being on the nitrogen atom, there is also a phenethylamine clause.
From erowid:
Phenethylamines#
Regarding phenethylamines, as of Febuary 2002 every single PEA described in PiHKAl as well as many variations not listed in PiHKAL are illegal in the UK because of the following additions to the law. A new catch-all phenethylamine clause which covers most known active PEA's. In particular this clause covers mescaline analogues, DOx, 2C-x, 2C-T-x, MMDA analogues, MDMA analogues TMA's and many others as well. the clause is:
"any compound (not being methoxyphenamine or a compound for the time being specified in sub-paragraph (a) above) structurally derived from phenethylamine, an N-alkylphenethylamine, alpha-methylphenethylamine, an N-alkyl-alpha-methylphenethylamine, alpha-ethylphenethylamine, or an N-alkyl-alpha-ethylphenethylamine by substitution in the ring to any extent with alkyl, alkoxy, alkylenedioxy or halide substitutents, whether or not further substituted in the ring by one or more other univalent substituents;"
The law includes a systematic explicit addition of every single PEA's found in PiHKAL that isn't covered by the aforementioned clause on the list of class A drugs.
In particular:
PEA substituted on the nitrogen of the sidechain with a subsituent other than alkyl (FLEA & the HOTs, MDAL, etc...)
PEA's substituted on the beta carbon (all the BOx,etc...)
PEA's with divalent substituents on the benzene ring (F-22, 2C-G-x,etc...)
Phentermine derivates
This revision has been skillfully designed so that not a single item of PiHKAL can escape to the law. In any case all the PEAs on the RC market are all covered by the catch all clause.
and tryptamines:
(b) any compound...structurally derived from tryptamine or from a ring-hydroxy tryptamine by substitution at the nitrogen atom of the sidechain with one or more alkyl substituents but with no other substituent.
and now the cathinone clause. The UK has some of the most restrictive laws regarding psychedelics. If you consider 4-MeO-PCP a psychedelic, it is legal in the UK, as well as 5-MeO-DALT so you're left with:
6-APB (accounts indicate it is not as psychedelic as MDA)
AMT
5-MeO-DALT
4-MeO-PCP
and then I guess there are some plants you can order that are not illegal to possess but probably illegal to prepare such as:
San Pedro/Peruvian Torch (extract mescaline)
Mimosa Hostilis (extract DMT)
HBWR/Morning Glory seeds (LSA)
aminita muscaria (dissociative muscimol and ibotenic acid)
and I guess some of David Nichols post-PiHKAL phenethylamines such as the FLY series may not be covered as the phenethylamine clause was designed to schedule all of the chemicals specifically listed in PiHKAL but I've rarely noticed there availability, except for 2C-B-FLY and Bromo-DragonFLY
salvia probably still legal?