Thousands of UK jobs will be at risk unless the government approves the commercial planting of genetically-modified (GM) sugar beet, according to scientific research.

The first detailed study of a single GM crop, suggests its commercial planting could cut the cost of producing sugar beet by 15%.

And the scientist who wrote the report has told BBC News that without it the industry may not remain viable - resulting in the loss of up to 20,000 jobs.

But environmental campaigners dispute the claims.

GM crops need less weed-killer, so should be cheaper to produce.

But the biggest user of beet, British Sugar, says growers could remain competitive without GM.

And, unless consumers' attitudes change, there would be no market for it anyway.