Pictured: brimstone, Gonepteryx rhamni
Notes from Jenyns: Common everywhere; & generally the first species of Butterfly on wing in the year, sometimes appearing as early as the beginning of February. ~ In the Autumn they frequent gardens in great numbers & appear much attracted by the flowers of the Red Valerian (Valeriana rubra). ~ The females are less common than the males. ~
200-year trend in Cambridgeshire: Little change.
Modern records
This species is still widespread and common across the county and as Jenyns says, is often one of the first butterflies that will appear in the new year.
National records map
Brimstone national records map: https://species.nbnatlas.org/species/NHMSYS0000516380