Sunday, 14 May, 2.30 pm: To me the River Idle, downstream from Retford at the Nottinghamshire Wildlife Trust Idle Valley reserve, looks pristine. Its clear with long tresses of water-weeds wafting in the current, although I haven’t spotted any fish darting around but its designation is that it has a ‘moderate’ ecological status, although it’s ‘good’ for invertebrates and fish get a rating of ‘high’.