Uncertainty leading up to Brexit worried the UK’s environmental consultancy sector and slowed its growth.

Environment Analyst, which surveyed “hundreds” of consultants and business managers, found growth and market projections for the sector as a whole have been damaged as a result of nervousness leading up to Brexit.

Average revenue growth fell to 4.4% in 2015, compared to 4.9% the previous year and 6.6% in 2013.

Companies with revenues worth more than £10 million saw growth fall more than the smaller environmental consultancies, which saw growth stay similar to last year.

One of the key influences in larger operator performance falling is the volume of large scale infrastructure work tailing off in recent years. Another is the vacuum created in the general election year as developers delayed decisions until policies and investment plans were clarified.

Although four in 10 of those questioned reported increased order books for the next 12 months compared with the last, 21% said order books were down at the beginning of this year.

Before the outcome of the EU referendum was known, the vote to leave was considered to be the single biggest business risk going forward by 59% of those surveyed, with only 21% thinking that it could provide a positive outcome.

A growing number of firms reported lower levels of international work – at 19% compared to 11% last year.