Council house debt has doubled in seven years amid the phasing-out of tenants' right-to-buy and borrowing to fund new building, official figures show.

Outstanding debt has risen from £1.8 billion in 2007/08 to £3.6 billion in 2014/15, according to Scottish Government housing revenue account (HRA) statistics.

The cost of servicing council house debt has risen by a quarter to £253 million and has overtaken property supervision and management (£240 million) as the second-biggest burden of council house expenditure behind repairs and maintenance (£362 million).

It is expected to rise even further to £282 million by the end of 2015/16.

About a sixth of the total debt is held by Edinburgh Council (£42.5 million), which is paying one of the highest interest rates in Scotland at over 5%.

Rents in Edinburgh have risen at about double the rate of the rest of the country, rising by half from around £60 a week in 2007/08 to over £92 a week.

The average Scottish rent has risen by around a quarter to £66 a week.

As a result, total housing revenue of £1.1 billion is forecast to exceed total housing expenditure of £900 million leaving a surplus of £205 million, which is expected to be reinvested in council house services.

More than half of council house revenue is financed by housing benefit provided by the UK Government, with £595 million provided through rent rebate subsidy for council house tenants.

Income from housing benefit ranges from 29% in the Shetland Islands to 72% in Dundee.

The report states: "Councils estimated that total HRA debt totalled nearly £3.6 billion as at March 2015, an increase of £350 million since March 31 2014.

"Part of the increase in debt since 2007 is a consequence of increased borrowing by councils to meet the capital costs of new build housing and improvements to existing houses and reductions in receipts from the sale of council houses."

A Scottish Government spokeswoman said: "All Scottish councils must ensure that their capital expenditure, and any resulting borrowing, is both affordable and sustainable.

"This is a decision for councils to take with reference to their housing strategy and requirements to utilise these funds for future development of existing stock or building new stock."