The population of the Western Isles is expected to fall almost 14% over the next two decades.

Depopulation has been described as the biggest threat facing the islands and the problem is growing faster than previously thought.

About 4000 fewer people will live in the Outer Hebrides by 2039, according to the latest estimates.

The Western Isles Council expects a 28% decline in the 0-15 age group, a 21% drop in the working age population and an 11% rise in the number of pensioners.

It previously estimated a total decline of just over 11%. About 27,000 people live in the islands.

Comhairle nan Eilean Siar will hold a series of meetings about the problem on November 7 and 8.

Council leader Angus Campbell said: "These figures sadly confirm what the Comhairle has been saying over the years.

"Population decline is the biggest threat facing our islands and action must be taken to stop and reverse the decline in numbers and the demographic imbalance.

"That is why we have been campaigning through the Our Islands Our Future campaign for more powers for the Islands so that we can do more to shore up our populations."

He added: "The Comhairle is doing everything in its power to make our islands an attractive place to live and work but we need more assistance from government at a UK and Scottish level to turn our aspirations into reality.

"Issues such as realising the renewable energy potential - which is dependent on a new interconnector - and control over the Crown Estate revenues and management will help give us the tools to do the job.

"Otherwise our people will continue to be forced to leave the Islands to seek work and we will be left with an increasingly elderly population and the stresses that puts on services in an ever more challenging financial climate."

In response to Mr Campbell's calls for greater assistance for the islands, a Scottish Government spokesman said: "Controlled and fair migration is essential to Scotland's future, both in terms of contributing to sustainable economic growth and mitigating the effects of demographic change.

"These figures show just how important migrants are to Scotland's demographic and economic growth. The Scottish Government has consistently called for a flexible approach to immigration across the UK.

"To support population growth the Scottish Government co-funds the COSLA Migration, Population and Diversity team which works across local authorities to ensure that Scotland is a welcoming place for new migrants, and to retain and integrate migrants to meet Scottish needs.

"We also provide £267,500 funding per annum to TalentScotland, a Scottish Enterprise-led service to promote Scotland as an outstanding place to live and work.

"However, these figures help to demonstrate that it is time that the UK Government started listening to Scotland and providing an immigration system that meets our needs."

A spokesman for the UK Government added: "We are working with the Scottish Government and other partners to grow the prosperity of all parts of Scotland.

"That includes hosting the annual islands summit, to discuss the particular concerns of remote communities."