Picking up the baton from Sir David Attenborough's Wild Isles, Countryfile launches 'Wild Britain', an ambitious 12-month initiative to galvanize us all to help and save our precious wildlife.Ellie Harrison and Hamza Yassin are lending a hand on the Lincolnshire Fens, as a group of local volunteers and school children begin the transformation of an old playing field into a wildlife haven by building a bog, a dead hedge and a bug hotel. Hamza also takes the children on a wildlife safari at a nearby nature reserve to show what nature their playing field could attract in a few years' time.Twenty years after his first visit, John Craven heads to Chester Zoo to discover how our smallest rodent, the harvest mouse, is getting on and takes a trip on the Macclesfield Canal to find out how we can all create our own wildlife haven, no matter what size of space you have. Tom Heap looks at the UK's track record for protecting nature, and if a new bill currently going through Parliament could undermine it. There will also be special appearances from nature lovers Dame Judi Dench and Deborah Meaden.