大象传媒

Julia Bradbury walks along the Offa's Dyke National Trail to celebrate its fortieth anniversary. She learns how sections of the 177-mile path are being opened up for disabled ramblers, and looks at how the dyke has become a treasure trove of ancient trees.

Joining her is Jules Hudson, who abseils off the stunning Pontcysyllte Aqueduct in search of the bats who have made this amazing structure their home.

John Craven investigates whether foreign invaders such as parakeets are out-competing our native songbirds, while Adam Henson witnesses a record-breaking attempt to shear a sheep and turn its fleece into a jumper in under five hours. But will the world record stand?

And the theme for the annual photographic competition is revealed, with the best entries forming the Countryfile calendar for 2012, sold in aid of Children In Need. Judge Chris Packham is on hand to provide some expert advice.