A good example of self-seeding. The neighbouring allotment is covered in Forget-me-nots. Self-seeders perpetuate themselves by depositing copious amounts of seed; disturbed ground is an ideal seed bed.
 Forget-me-nots are of the Myosotis genus in the Boraginaceae family. These are most likely to be the Wood Forget-me-not (M. sylvatica) or the Field Forget-me-not (M. arvensis) which look very similar. Given the locale I would think they are the latter. They have a prolific but brief life span and the capacity to behave as annuals, biennials or short lived perennials according to the conditions.