<p>About 9,000 units of new prime residential development , worth around £9 billion, is on site or planned for delivery in central London up to 2020 according to a report out today from EC Harris.</p> <p>Of that total, 4,000 units (£8 billion) are likely to come to the market in 2014-15.</p> <p>The research is based on a snapshot analysis of new private residential development projects currently being built or planned for delivery in central London through to 2020 using an estimate of development programmes, units, saleable areas and sales values.</p>