Leading countries that supply wood products to the UK face running out of timber in the next few years, a report has warned.

Key suppliers have only a few years of available timber forest left or are "running at a deficit", having used up all the sustainable and legal timber since 1990, and are now cutting down protected forests, it said.

And the amount of wood the UK needs that is grown in Britain is expected to fall from 40% to 22% by mid century, as a result of falling planting levels since the 1970s, the study from conservation charity WWF said.

WWF issued the warning that UK businesses face a timber supply crunch, amid expectations global demand for timber will treble by 2050 as economies and populations, and their need for wood and paper products, grow.

It is calling on businesses to invest now in sustainable forest management to ensure they have access to the timber they need in the near future.

The charity's report on the business and economic case for sustainable timber revealed that Brazil has only 16 years of timber forests remaining, South Africa has seven years and Colombia 12 years.

It also warns that primary forest is being cut down at an alarming rate, with Nigeria losing 99% of its original natural woodland since 1990, and Vietnam losing 80% since then, with serious impacts for wildlife and natural resources.

In the UK, new planting has fallen by a third since the 1970s and foresters interviewed for the study expressed grave concerns over the future of UK softwood supplies in the next 10 to 30 years.

The proportion of timber sourced in the UK will fall significantly to 22% by 2050, if not sooner, the report said.

To boost commercial forestry without damaging the other values of woodlands such as wildlife and recreation, the report recommends bringing unused or underused forest back into management and planning forestry at a landscape scale.

It also urges planting trees which have a commercial and wildlife value.

Julia Young, global forest and trade network manager for WWF-UK said: "Committing to sustainable timber sourcing isn't just an added bonus, but is something that any timber dependent business must be investing in if they want a healthy and resilient business that will survive.

"We can no longer rely on our usual sources of timber as unsustainable practices are having devastating consequences on forests, and we face a real danger of not having enough timber to satisfy our growing population needs.

"Businesses need to review how their timber is sourced if they want to secure supply for the future, and keep timber prices stable."