Ananova:

Gordon Brown has reached out to first-time buyers by promising to accelerate house-building and increase the availability of affordable homes.

The Prime Minister set out his ambition for three million new properties by 2020 - some 250,000 more than the Government's existing target.

He also moved to reassure environmentalists by ruling out a review of the green-belt map and insisting that new homes would be built "principally" on brownfield sites. His comments came after Communities Secretary Hazel Blears raised fears of a foray into the green-belt when she appeared before MPs on Tuesday.

In a pre-announcement of the legislative programme to be set out in the Queen's Speech later this year, Mr Brown gave centre stage to his efforts to assist would-be homeowners and improve social housing provision. Measures will include acquisitioning hundreds of disused publicly-owned sites for new homes and a streamlined planning system to ensure that major building programmes are waved through more quickly.

"Putting affordable housing within the reach of not just the few, but the many, is vital both to meeting individual aspirations and to securing a better future for the country," Mr Brown told MPs.

The plans were welcomed by housing organisations and builders, but the Tories insisted Mr Brown was himself responsible for "kicking a whole generation off the housing ladder" through the tax regime.

Mr Brown pledged a Housing and Regeneration Bill to merge English Partnerships and the Housing Corporation into a new agency tasked with increasing social and affordable housing. A major part of its job will be to bring public sector land into use for house-building. More than 550 Government-owned sites are under consideration to make way for 100,000 new homes, while councils are under pressure to give up brownfield land with space for another 60,000.

English Partnerships is already working with the Ministry of Defence to release six or more sites with space for more than 7,000 properties. Further negotiations are under way with the Department for Transport, the Highways Agency and the British Railways Board Residuary Body, while the Department of Health is urgently reviewing its surplus land.

The new homes agency will also be required to enter partnerships with councils, health authorities and the private sector to provide more shared-equity projects and increase the social housing stock.

The Bill will enable fresh investment in social housing infrastructure - as opposed to the present system of grant funding - as councils are urged to lead new house-building programmes. A Planning Reform Bill will also be introduced in the next Parliamentary session to speed up major housing infrastructure projects by streamlining the planning system. Mr Brown said that the new homes would be "principally" built on brownfield sites but dismissed any suggestion that the Government would re-draw the green-belt boundaries.