With the waters receding, Bang Goes the Theory takes a more considered look at the recent floods. Did global warming play a part, or is this simply the extreme end of the natural cycle? Maggie investigates the real threat of storm surge as water levels rise, Liz Bonnin looks at how to use nature to 'slow the flow' and the team are joined by Charlie Dimmock who wants to know if her love for patios and decking might have played a part in creating urban flash floods.