The body teamed up with the ENDS report to survey environmental professionals, and found 52 per cent believe energy and climate policies would be most likely to come under threat.
The Water Framework Directive and the Waste Framework Directive also came among the top laws most likely to be missed, with 42 per cent and 32 per cent of respondents referencing them respectively.
A number of respondents to the survey pointed out that no EU environmental rules would cease to apply on exit, but a post-Brexit UK government would have greater freedom to start making changes.
Respondents to the Institute of Water survey came from across the environmental spectrum, from water and waste to energy and nature. The most common were water (35 per cent), waste (32 per cent) and energy (28 per cent).
Two thirds of respondents said they would definitely vote ‘remain’, while only 3 per cent are entirely undecided.
Source: ENDS Report
Respondents believe by a very large margin that membership has been good for UK environmental protection and sustainability, with about 85 per cent saying the EU’s impact has been ‘good’ or ‘very good’. By contrast, just 5 per cent who see it as ‘bad’ or ‘very bad’.
ENDS spoke to a number of respondents in depth after the survey.
Keith Clarke, vice-president of the Institution of Civil Engineers and chair of Swansea Bay Tidal Lagoon, said: “I don’t think the UK would have got anywhere close to the same level of air quality and water legislation without Europe.
“It has led on substantive environmental legislation which I think has been entirely constructive. We could have done it. We could do it in the future. I just don’t believe we would.”
Anita Lloyd of law firm Squire Patton Boggs said: “I don’t think it’s fair to say we would continue to have been the ‘dirty man of Europe’ and would not have had a reasonable level of environmental protection. But I think the EU has gone further on, for example, water quality and habitats.”
Survey respondents strongly agreed that if Britain votes ‘leave’ in June, it should still stay in the European single market.
Source: ENDS Report