The law of the desert dictates that if a group of people dig a well they have the first right of use of the well, but they cannot deny the use of drinking water to others: man or beast. The convention also dictates that those lowering a container into the well have the right to possess as much water as the container holds, but not a drop more, without acquiring ownership of the water source.

Groundwater is by far the largest source of freshwater, accounting for 67 per cent of the world's resource and is found in underground aquifers. Groundwater has little appreciation for the sovereignty of nations flowing into rock layers, pushed along by gravity and discharging at will either as springs or adding to rivers, helping to maintain the planet's ecological balance. The world's surface water (accounting for 1 per cent of global freshwater) in the form of rivers equally has scant recognition for man made borders with the currents of the Nile passing through nine nations.

So can this life-giving source ever be owned? Even international law is imprecise. Although there is a generally accepted belief that water itself cannot be owned, there is a global acceptance that the methods by which a person, legal entity or nation, stores, transfers and regulates the flow of water makes them the person in control or, the one with their "hand on the tap".

This control has already led to many "water wars" over the years such as the 1967 six-day war between Israel, Jordan and Syria, which according to Ariel Sharon arose out of proposals by Jordan to build dams that would severely impact on Israel's water supply. In the late 1980s, Senegal and Mauritania fought across the Senegal River, wars in which Syria, Iraq, Libya and Saudi Arabia all became embroiled.

The present day possibility of terrorists targeting Saudi Arabia's desalination plants, responsible for over 30 per cent of global production, would have far reaching and devastating effects. With Kuwait and all the other Gulf States reliant on desalination plants, the size of small cities, water, or the lack of it, could prove the biggest WMD for the region.

If this all seems a world away, then consider this. In the USA, groundwater accounts for 50 per cent of livestock and irrigation use and in rural areas 96 per cent of domestic water use. Recently though, concerns regarding the depletion of finite fossil water supplies have gained momentum. The Colorado Basin, servicing the states of Arizona, California and Nevada is at its lowest level in 30 years. To allay fears of an imminent drought, plans are under discussion to build a $1bn pipeline to bring water from other regions to the water hungry Napa and Nevada valleys. Many environmentalists are unhappy with the scheme and believe that the voracious appetite for water by the Nevada tourist industry with its deluxe hotels should not be subsidised to the detriment of the environment and wildlife of less arid regions.

Here in the UK, August rainfall levels were some of the highest recorded yet, groundwater levels remained below average at more than 50 per cent of indicator sites. As populations grow, so does the need for freshwater, but the supply is not infinite. This year has resulted in steep rises in water bills with some customers paying 45 per cent on average more. Someone indeed appears to have their hand on the tap.