David Cameron's big policy announcement about extending the right to buy to social housing had no immediate resonance in Scotland.

Housing is devolved, and the Scottish Government has turned its back on the right to buy policy.

That doesn't mean housing associations in Scotland aren't worried about it. How the Tory policy will be paid for isn't clear and so neither are the implications it might have for funding new housing in Scotland under the Barnett consequentials.

However the announcement also drew attention to the complexities of an issue like housing in which responsibility falls in a complicated and awkward way between Holyrood and Westminster, and where the Smith Commission proposals will further alter the balance.

A gradual, unintended shift has seen Westminster take on the bulk of responsibility for financing social housing. Despite policy being devolved, rising rents have left rising numbers of tenants reliant on housing benefit support to pay for their housing. The annual value of rent support, which is reserved to Westminster, is now almost twice as much as the value of annual housing investment, which is devolved to Holyrood.

Wht happens at Westminster still matters to housing in Scotland. One huge looming problem is Universal Credit. The new benefit, currently being rolled out, incorporates housing benefit with a number of other benefits into a single monthly payment.

Fears over the ability of vulnerable tenants to budget have been addressed by plans to hand Scotland greater powers, which will include the ability to vary the housing element of Universal Credit.

But given the introduction of UC has already been more or less a complete shambles, more than 50 charities and housing providers, have written to the DWP calling for a temporary halt to its roll out.

It surely doesn't make much sense to introduce such a complex change, only for the system to be thrown into turmoil again a short time later when Scotland gets new. But Iain Duncan Smith has rejected any delay.

More devolution of social security is called for by many, but the experience of Northern Ireland, which has, such powers is that in reality they have been difficult to use.

Such issues where policy is in limbo between Westminster, Holyrood and Smith, complicate the policy landscape ahead of next month's election.

One essential factor will be close collaboration between the two governments to ensure arrangements over issues such as Universal Credit are handled smoothly.

Is that likely? Already the Secretary of State is meant to consult Scottish ministers before implementing welfare reforms that would affect Scotland. Evidence that this has made the slightest difference over the last five years would be hard to find.