Liquid London

While today we take the stuff for granted: turn a tap and it gushes out, it wasn't always so. For centuries the metropolis, one of the largest and richest cities in the world, struggled to keep its citizens hydrated with reliable, clean water.

From the elm-wood pipes of Tudor London via dragon-like early steam engines to Thames Water's blue tubes, where has our water come from?

London historian PETER STONE tells of some of the most signifcant developments in the city's early hydration history - the London Bridge waterwoks and the contruction of the picturesque New River, which was neither new nor a river but an extraordinary aqueduct completed in 1613 to pipe fresh water into a polluted city. The company that built it was one of the very first modern business corporations, and also one of the most profitable and the New River amazingly remains part of London's water supply today.

Journalist NICK HIGHAM takes up the tale - from the 18th Century to the present day - and it’s a tale of technological and organisational breakthroughs; Chelsea Waterworks was the first in the world to filter the water it supplied its customers and the same technique is still used to purify two-thirds of London's drinking water.

But it is also a story of greed and complacency, high finance and low politics - for much of London's history water had to be rationed and one Victorian London water company deliberately cut off 2,000 households, even though it knew they had no alternative source of supply. Nick asks whether today's 21st century water companies are an improvement on their Victorian predecessors.