This helps

http://www.planningresource.co.uk/article/1367438/conservatives-2015-five-messages-minister-manchester

In short it appears that the intention is to crowbar 'starter homes' (i.e. market housing sold at a 20% discount to first time buyers under 40), into the definition of affordable housing. The current definition in the NPPG and the NPPF is given below. As the definition is in the NPPF and the NPPG, it may be that an amendment to both would be required.

I'm not sure what impact this would have. Without appropriate consultation and impact assessment, the proposed change, as with the previous affordable housing thresholds and exemptions, would be open to challenge. Furthermore, the previous Court Judgement confirmed in no uncertain terms that adopted local policy must be given primacy and national guidance (e.g. NPPG) is only guidance to be given appropriate weight. Therefore, if a LPA has adopted policies which seek to secure affordable housing and identify that an appropriate tenure mix should be secured (which will not include 'starter homes' in most cases), it appears that these policies would retain primacy.

It may turn out to be another case of Government winging it and hoping Council's will play ball.

‘Affordable housing: Social rented, affordable rented and intermediate housing, provided to eligible households whose needs are not met by the market. Eligibility is determined with regard to local incomes and local house prices. Affordable housing should include provisions to remain at an affordable price for future eligible households or for the subsidy to be recycled for alternative affordable housing provision.

Social rented housing is owned by local authorities and private registered providers (as defined in section 80 of the Housing and Regeneration Act 2008), for which guideline target rents are determined through the national rent regime. It may also be owned by other persons and provided under equivalent rental arrangements to the above, as agreed with the local authority or with the Homes and Communities Agency.

Affordable housing: Social rented, affordable rented and intermediate housing, provided to eligible households whose needs are not met by the market. Eligibility is determined with regard to local incomes and local house prices. Affordable housing should include provisions to remain at an affordable price for future eligible households or for the subsidy to be recycled for alternative affordable housing provision.

Social rented housing is owned by local authorities and private registered providers (as defined in section 80 of the Housing and Regeneration Act 2008), for which guideline target rents are determined through the national rent regime. It may also be owned by other persons and provided under equivalent rental arrangements to the above, as agreed with the local authority or with the Homes and Communities Agency.

Affordable rented housing is let by local authorities or private registered providers of social housing to households who are eligible for social rented housing. Affordable Rent is subject to rent controls that require a rent of no more than 80% of the local market rent (including service charges, where applicable).

Intermediate housing is homes for sale and rent provided at a cost above social rent, but below market levels subject to the criteria in the Affordable Housing definition above. These can include shared equity (shared ownership and equity loans), other low cost homes for sale and intermediate rent, but not affordable rented housing.

Homes that do not meet the above definition of affordable housing, such as “low cost market” housing, may not be considered as affordable housing for planning purposes.’

The full speech is given here:

http://www.mirror.co.uk/news/uk-news/david-camerons-full-speech-conservative-6589711

But for me, there’s one big piece of unfinished business in our economy: housing. A Greater Britain must mean more families owning a home of their own. It goes back to those Conservative beliefs: reward for hard work. If you’ve worked hard and saved, I don’t want you just to have a roof over your head – I want you to have a roof of your own. In the last 5 years, 600,000 new homes have been built. More than 150 people a day are moving in thanks to our Help to Buy scheme. And in our manifesto, we announced a breakthrough policy: extending the Right to Buy to housing association tenants. Some people said this would be impossible. Housing associations would never stand for it. The legislation would never pass. Let me tell you something. Greg Clark, our brilliant Communities Secretary, has secured a deal with housing associations to give their tenants the Right to Buy their home. That will mean the first tenants can start to buy their homes from next year. Yes, as we said in our manifesto, 1.3 million to be given the chance to become homeowners. A promise made. A promise kept. But the challenge is far, far bigger. When a generation of hardworking men and women in their 20s and 30s are waking up each morning in their childhood bedrooms – that should be a wakeup call for us. We need a national crusade to get homes built. That means banks lending, government releasing land, and yes – planning being reformed. And in all these things I’ll be working with a great London Mayoral candidate – and, I hope, soon to be our London Mayor – Zac Goldsmith. But I want to single someone out. He’s served this country. He’s served this party. And there’s a huge amount more to come. So let’s hear it for the man who for two terms has been Mayor of the greatest capital city on earth: Boris Johnson. Increasing home ownership means something else. For years, politicians have been talking about building what they call “affordable homes” – but the phrase was deceptive. It basically meant homes that were only available to rent. What people want are homes they can actually own. After all, the officials who prepare the plans for the new homes, the developers who build them, the politicians who talk about them… …most of these people own the homes they live in. Don’t they realise other people want what they’ve got – a home of their own? So today, I can announce a dramatic shift in housing policy in our country. Those old rules which said to developers: you can build on this site, but only if you build affordable homes for rent… …we’re replacing them with new rules… …you can build here, and those affordable homes can be available to buy. Yes, from Generation Rent to Generation Buy… …our party, the Conservative party… …the party of home ownership in Britain today.

Isn’t it just a way to get around the recent legal challenge to the government threshold for affordable housing?

By announcing that starter homes are really just a form of affordable housing, developers will presumably be more disposed to local thresholds since they wont have to go into partnership with Housing Associations or pay commuted sums ?