Invasive ladies...
Our office was swarming with these nasty critters last year. They are Harlequin Ladybirds. On a plus they do eat aphids BUT so do our native ladybirds and these are the ones who are under threat.
In general Harlequin Ladybirds are larger and have more spots that our native ladybirds.
Think you've found one? The University of Cambridge, CEH and Anglia Ruskin University are doing a survey of Harlequin ladybirds. You can use your mobile or the web to record your sightings. Just click here to find identification sheets and more info. Another great site for native ladybird fans is http://www.ladybird-survey.org/