Easily mistaken for : Burnet-Saxifrage (Pimpinella saxifraga) but that is shorter and has longer leaflets singly-pinnate leaves with more leaflets.
Easily mis-identified as : Lesser Water-Parsnip (Berula erecta) but that has bracts beneath the umbels and bracteoles beneath the umbellules.
Some similarities to :
Greater Water-parsnip (Sium latifolium) but that too has bracts beneath both umbels and umbellules and at up to 2m high is far taller.
No relation to :
Burnets such as Great Burnet (Sanguisorba officinalis), Salad Burnet (Poterium sanguisorba ssp. sanguisorba) or Fodder Burnet (Poterium sanguisorba ssp. balearicum) [plants with similar names from the Rose Family (Roseaceae)] nor to any Saxifrages such as Meadow Saxifrage (Saxifraga granulata), Starry Saxifrage (Saxifraga stellaris) or Mossy Saxifrage (Saxifraga hypnoides) [plants from the Saxifrage Family (Saxifragaceae)].
It is native and grows on shady grassy road verges, hedgerows and in the dark margins of woods within the enlarged central area of the UK (encompassing Lancs, Yorks, Derbys, Midlands, Shropshire, Leicester and those counties inbetween) with populations also occurring in Kent and South Devon.
The leaves of this plant (which are mostly singly-pinnate, but a few are bi-pinnate) are variable with regards to both the shape and the teeth of the leaflets of which it is constructed. Wikipedia makes mention of five varieties, which may account for the variability in leaflet shape, assuming that these also grow in the UK. The varieties mentioned are rosea, macrodonta, orientalis, dissecta and bipinnata, with the varietal name seemingly accounting for at least some of the reported possible leaf shapes. But UK plant ID books make no mention of these varieties!
A famous immediate relative of this, in the same Pimpinella genus, is called
Anise (Pimpinella anisum) (which should not be confused with the totally un-related (they are not even from the same Apiaceae / Umbellifer family)
Star Anise (Illicium verum) nor with
Japanese Star Anise (Illicium anisatum) which have similar but not identical tastes - but are less expensive to produce than Anise itself, which has rapidly lost ground to these near-substitutes). Anise is used to flavour Aniseed Balls and several liqueurs such as Ricard, Pernod, Ouzo, Absinthe, Abisette and Sambuca amongst many others from around the World.