The Striped Shieldbug, also spelled Shield Bug, is a distinctive red shieldbug with thick black lines on its back and, depending on species/individual, black spots or lines on its "shoulders".
It was previously a Mediterranean bug but late last century the striped form (G. italicum, with black legs) travelled to northern continental Europe and may subsequently colonise the UK.
The spotted form (Graphosoma semipunctatum) above, with lines on its back and spots on its thorax, although some spots are joined! The legs are red and the "skirt" is all black rather than red/black.
The underside of all three species is red with black spots.
Some of the spots on G. semipunctatum join as lines
Unsure whether this one is a melanistic G. semipunctatum or, with continuous stripes, is G. lineatum (G. italicum has black legs). It was in the same vineyard in Tenerife as the others shown above.
The shieldbug above has black "thighs" and blackish-red tibias, with a black and red striped "skirt". Possibly G. lineatum/italicum -- photographed in southeast Kazakhstan.