The housing crisis facing London's key workers is set to worsen as figures reveal the capital is building less than 30% of the new homes it needs. <p></p><p>In his spatial development strategy London mayor Ken Livingstone is seeking to increase the supply of new homes by at least 23,000 a year. He says 43,000 new homes are needed annually, 28,000 of which should be &amp;"affordable&amp;" to reduce the numbers of nurses, teachers and police officers fleeing the capitalÕs high house prices. But just 12,000 new homes were built last year. </p><p>Livingstone is continuing to press for a 50% rate of affordable homes, 35% of which should be low cost and 15% should be intermediate housing for people on modest incomes. </p><p>The HBF argues that there is now so much pressure for developers to pay for ever-increasing quotas of affordable housing that many sites are no longer economically viable and it is better to have 20% of something rather than 50% of nothing. </p><p>Against this backdrop and the ongoing question of affordability, HBF has produced a new<i> Guide to Developers for Negotiation in Affordable Housing</i>. It is designed to help housebuilders in their contact with local authorities at all stages of …