The soil in Britain is so contaminated that it is damaging construction efforts across the country, according to a report from the Environmental Audit Committee (EAC) out today.
Around 300,000 hectares of UK soil are thought to be contaminated with toxic elements as a result of the country's industrial history, and London is one of the worst affected areas.
The report says: "Past industrial sites have left a legacy of soil contaminated by the disposal of waste materials on site and the demolition of buildings containing toxic elements, such as cadmium, arsenic and lead, at levels which are detrimental to human health.
"This contaminated land restricts the use of brownfield land for urban development."
Better use of brownfield sites could help provide an extra 1.4m homes for London – but the capital is a hot-spot for contamination. This map shows the concentration of lead in topsoil across Britain.
The committee branded the Department for Environment, Food and Rural Affairs (Defra) "complacent" for removing capital grant funding for local authorities to clean up sites and allow for developers to build.
The MPs estimated the cost of soil degradation in England in Wales is between £0.9bn and £1.4bn per year.
Mary Creagh, chair of EAC, said: "Our industrial heritage means that hundreds of thousands of sites across the country are contaminated by chemicals, heavy metals, tar, asbestos and landfill. Often materials were disposed of on site and buildings demolished without the environmental safety regulations we take for granted today.
"Defra's complacent decision to withdraw contaminated land grants has undermined the ability of councils to identify and clean up polluted brownfield sites not dealt with through the planning system."