In 2012 roads became rivers, rivers swelled to raging torrents and green fields turned into vast, spreading lakes. It was the year Britain flooded.

The relentless and unprecedented levels of rainfall had little respite; it was England's wettest year since records began. Yet 2012 had started so well.

After months so dry that garden hosepipes were banned, the drought broke and the rain started to fall, making April the wettest month ever known in Britain.

The weather got worse: more than twice the average rainfall in June created the wettest summer in a century, and 2012 became officially the second wettest year ever recorded in the UK.

This documentary reveals how a combination of meteorological and geological factors created the year of the flood.

Taking to the air with weather experts and diving into Britain's sewage system and saturated underground aquifers, the programme explains why the floods occurred and shows how devastating they can be.

It's not just the overflowing content of your local river that can be hazardous to health, but also the pollutants pouring upwards from drains and sewers.

With dramatic eye-witness accounts of the worst of the country's floods, moving human stories and expert interviews with meteorologists, geologists and climate scientists, this film reveals exactly what happened in the year Britain flooded.