Figures from the Halifax show the average house price in London was £237,760 last year, compared with £141,326 in 2000. Government sources said workers in their twenties on about £21,000 a year would need to save for 17 years for a deposit in the capital. Mr Duncan Smith said it would be "easy" for ministers to "shirk our responsibilities" to young people, but "that attitude must be consigned to history, otherwise we will bear responsibility for the burdens on our children".