Queen turns on the tap

The Queen has agreed to officiate at the opening of Thames Water's ring main, the pounds 250m tunnel which the company has been building since February last year and which will be able to supply 50 per cent of London's demand for drinking water.

The ring main, part of which runs under Buckingham Palace Gardens, has a capacity of up to 1,300 million litres per day - enough to fill the Albert Hall eight times. It provides water for an area of 580 square miles and more than half of the tunnel is already in use.

The Duke of Edinburgh will also be present at the ceremony on 11 November at Ashford Common, Sunbury.