Barley-type winter cover crop?

Barley-type winter cover crop?

Observation - Barley-type winter cover crop? - UK and Ireland. Description: I first saw this type of crop last winter, in the same location or nearby. It appears to be barley,

I first saw this type of crop last winter, in the same location or nearby. It appears to be barley, and is flowering at about 60 cm high, However, it obviously can't be being grown as a grain crop, so what's its purpose? I've googled, and asked around a bit, but no-one seems to know. It isn't an accidental 'crop' from dropped seed, as it's clearly been drilled in rows.
It's also growing north of the coast road (A 149) between East and West Runton. My guess is that it's some sort of cover crop - but what are the advantages of 'barley' as opposed to eg the more usual brassicaceous crops one sees?