Gatekeeper (Pyronia tithonus).

As its name suggests, the Gatekeeper (also known as the Hedge Brown) is often encountered where clumps of flowers grow in gateways and along hedgerows and field edges. It is often seen together with the Meadow Brown and Ringlet, from which it is easily distinguished when basking or nectaring with open wings.

The colour and patterning of the wings are very variable and about a dozen aberrations have been named. Favourite nectar sources include Wild Marjoram, Common Fleabane, Ragworts, and Bramble.

Source: Butterfly Conservation.