The deceiver (Laccaria laccata) is considered by some to be the most common species of British fungus but it is very variable, or deceiving, and appears to be several species all at once! It is quite plain with few distinguishing features which makes it even harder to be certain that it is what it is. It can be found in broad-leavved and coniferous woodland, on heaths and amongst short grass anywhere, often where there is birch nearby.
Usually appearing in small troops in summer through to winter. It may be edible, it may not, my books do not say, so I would leave well alone!