Health campaigners are urging the government to do more to tackle air pollution in the capital as new figures show it is a factor in thousands of deaths.
Clean Air London claims that air pollution is killing more then ten times the number of people who die from road traffic accidents.
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The strikebreakers would provide a "pool of relief staff" so the city could still operate during the Tube strikes.
Dean Waite's prints of London icons are made with little more than a biro.
Ahead of tonight's planned strike, London Underground have offered new payments and terms to staff to avert the strike.