Confidence: I'm as sure as I can be.
Notes: Fern lesson 2. Look to see how many pinnate the fern is, in this case it's bi-pinnate. Polypodies are 1 pinnate so it's not one of them I'm afraid. Then, and of course one can't do this from a photograph, turn it over. From general appearance this looks like a Dryopteris sp, the bipinnate species being known as Male Ferns. You could confirm by turning the frond over and looking at the spore cases. In Dryopteris these are kidney shaped. After that look at the junction between the side branches and the main stem. If there's a black dot, or staining then it's likely to be one of the three Scaly Male Ferns (and telling them apart is a job for an expert), if not, and you're not in an upland area then you have D. filix-mas, the Common Male Fern (which this probably is). If your in the hills you should consider D. oreades (Mountain Male Fern). But that's another story.