I think it’s a Shield Bug or an Instar (a developmental stage of Shield Bugs). There are lots of different sorts.
Hopefully @wild edges or someone who knows more will be along with more info soon.
We love them … they’re such handsome creatures.
Googling reveals all sorts of worrying stuff about ‘Stink Bugs’ and damage to plants but that relates to the USA. The ones in the UK do little if any damage and are simply part of the amazing ecosystems in our gardens.
Enjoy 😊
Gardening in Central Norfolk on improved gritty moraine over chalk ... free-draining.
It is one of the larval stages ( instars ) of the green shield bug - I'm guessing 1st or 2nd skin shedding in -- as they mature they get to more evenly green in colour ( vs green and black).
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Gardening in Central Norfolk on improved gritty moraine over chalk ... free-draining.
In the sticks near Peterborough