Environment Agency's (EA) annual document, published on Wednesday (July 10), said the water company 'consistently demonstrated unacceptable performance' in 2018. The report said South West Water (SWW) had the most pollution incidents of the nine companies with 98 per 10,000km - more than double the next largest which is Yorkshire Water with 44. SWW said the company achieved its best wastewater performance last year but recognised there is still more work to do. The environmental performance assessment rates each of the nine water and sewage companies in England as either green, amber or red on a range of measures including pollution, supply resilience, self-reporting of pollution and complying with permits. SWW was given a 'red' rating and a two-star score for performance - the highest is four stars. EA said overall water company performance across the country has deteriorated, reversing the trend of gradual improvement in the sector since the rating system began in 2011. Emma Howard-Boyd, EA chairman, is pledging the agency will continue to work with the water services regulation authority to look at possible financial penalties. She said: "Companies should be reflecting on their environmental performance and long-term resilience, if this is poor they should be asking themselves whether dividends are justifiable." A South West Water spokesman said: "We have an action plan in place to continue to drive improvement, focusing in particular on further reducing those that have a minor or minimal impact on the environment - the only area where the EA assess that we are below the industry average. "This includes continued investment in our monitoring capabilities, equipment, site upgrades and staff training. "We are also working closely with our regional suppliers and universities to develop enhanced 'network intelligence' techniques. We have already demonstrated further progress in 2019. "We remain on track to deliver our 2020 targets where we are aiming for zero serious and significant pollution incidents, a further reduction in other incidents and 100 per cent compliance with wastewater permits. "We will continue to work alongside the Environment Agency to achieve this."