I think that even though it is incredibly difficult to get a mortgage today, that's probably not a terribly bad thing. but that mortgages should be based on affordability, not deposit saved. (which would avoid the situation I actually found myself in when a mortgage company said that they didn't believe that I'd be able to service mortgage repayments. [and that instead i should rent in a market when rental prices were higher] or at least an intelligent balance between the two.
honestly, I'm not sure that there is a neat solution that can be wrapped up into a single post.
but as suggestions that I've seen in the past:
Compulsory purchase of homes that are neither occupied or advertised for rent. There are millions of empty houses. (which is just as messy as the "right to buy" idea that started the thread!) (but at least gets more social housing available without the need to build new properties on previously undeveloped land.)
Charging a levy on empty homes, this would provide incentive to lower the rents to get houses occupied - though it would also provide incentive to raise the price once tenants thought that they were secure. (so it has it's own issues) but lower rents make for easier savings, introducing this extra risk would reduce the "pull factor" to become a BTL landlord, reducing pressure on the market would reduce demand, and cause prices to fall. (it would also deter buy to leave foreign investment)
Or finally build more houses.
many many more houses.
Of course the trouble with this is as follows. lets assume that developers do build a million homes in and around London (somehow) supply would outstrip demand. house prices would fall. newer buyers would find themselves with negative equity. landlords would not only find that they had negative equity. but that the amount of rental income they might expect from their property would also be reduced.
but developers won't add a huge amount of homes into the system (lets face it why would they give over huge amounts of cash to build houses and in doing so devalue the very houses that they are building?)
Which leaves the best option of: increase supply of council/housing association properties. (and possibly get rid of right to buy)
Accept that a huge increase in supply for social housing would mean that the private rental market would take a hit. when the private rental market takes a hit that would mean directly affecting buy to let properties, and the supply demand price issues that are faced...
I guess the real issue is, (and I'm not making any kind of judgement on the home owners or landlords here):
you have worked hard.
you have gone without.
you have saved hard and bought a house, in fact bought multiple houses and rented some out.
at great personal risk.
You must be aware that the final option of "get the government to build more houses, to reduce both rental and commercial market pressure" would almost certainly mean "let's raise taxes".
Do you really want to pay more tax to fund the development of a program that will see your hard fought for business worse off?