A fragile-looking bug found on Hedge Woundwort (Stachys sylvatica). It is bright green with dark antennal bases, and a dark line between the eye and pronotum.  The antennae are shorter than the very similar M rubi, and the 3rd antennal segment is c.1.75x the length of the 4th (last) segment. 

Macrolophus rubi

A good field photo plus a close up of the specimen showing the the relative lengths of 3rd and 4th antennal segments.  You must note the food plant.  We recommend that a specimen is retained in case expert verification is needed 

Woodland edges, hedgerows etc on Hedge Woundwort

Widespread; due to confusion in the past with M rubi the range is not clear. (ref. British Bugs webpage for the species)

Rarely recorded

British Bugs https://www.britishbugs.org.uk/heteroptera/Miridae/macrolophus_pygmaeus.html