A slowing of jobs in the U.K's renewable energy sector can be blamed on inaction by lawmakers after a turbulent year of politics, according to a new study.

Just under 126,000 people were employed in the U.K.'s renewable energy industry in 2015/16, according to the Renewable Energy Association's (REA) REView 2017 report on Monday.

These jobs – including the renewable heat, power and transport sectors – represent a 2.5 percent increase compared to 2014/15. This, however, is sharply lower than the 8.8 percent growth recorded between 2012/13 and 2013/14.

Other key findings from the report include renewable energy industry turnover hitting £17.4 billion ($22.6 billion) in 2015/16, a 3.5 percent increase compared to the previous year, although the number of businesses operating in the renewable energy sector fell by 5 percent.

"It shows real progress that there were nearly 126,000 jobs in renewable energy in 2015/16," Nina Skorupska, chief executive of the REA, said in a statement on Monday. "This is in addition to over 16,000 in energy storage and in electric vehicles, which is the first year we have reported on these sectors."

"What is deeply frustrating is that this growth could have been greater," Skorupska added. "Policy instability in Westminster has slowed growth. Our member companies are helping build a system that is reliable, low-carbon and more affordable than the previous one."

Government action was required to "ensure the opportunity to be leaders in technologies such as energy storage and decentralised systems does not slip between our fingers," Skorupska went on to say.

The REView publication was compiled using employment data from independent consultancy Innovas as well as investment data and analysis from KPMG.