The small red creatures that you found in your garden are commonly known as velvet mites, Allothrombium fuliginosum. This animal overwinters as adult mites in the soil and it is most frequently found at this time of year when it is seen crawling over the soil surface. It is not a harmful mite as the early stages feed as external parasites on certain insects, particularly aphids. The older mite nymphs and the adults feed as predators on aphids. Velvet mites are widely distributed in Britain and may have some effect in reducing aphid infestations, although their impact is likely to be much less than that of other aphid predators, such as ladybirds and hoverfly larvae.