The trove has been donated to the SS Great Britain Trust and Brunel Institute.Nick Booth, head of collections at the Trust, said: “The documents provide a remarkable and unique insight into Brunel in his formative years.“It would be going too far to suggest Brunel was an environmentalist – he was a Victorian engineer after all – but this does provide a glimpse of genuine concern about pollution and is perhaps another way Britain’s greatest engineer was way ahead of his time.” The documents didn’t stand out “until I got to the bottom of the first letter and to my amazement realised it was signed IK Brunel,” Mr Henley said.The letters, dated between 1832 and 1846 and most of them addressed to the Bristol Dock Company, throw fresh light on the period in which he was appointed engineer to Clifton Suspension Bridge, launched the SS Great Britain and completed the Great Western Railway. Researcher Roger Henley unearthed the letters among thousands of archive documentsCredit:Bristol Port Company Isambard Kingdom Brunel expressed fears that the Industrial Revolution was harming the environment, according to newly discovered letters.The engineer worried about water supplies being polluted by waste, some of it created by his Great Western Railway.Writing in 1842 about Bristol’s floating harbour, he said that “the abuses of using the Float as a common receptacle for rubbish have immensely increased”. He also cited waste from the local cotton mill, iron merchants, and ship, locomotive and bridge builders.The pollution was “in some measure unavoidable”, he wrote, but too many were using the harbour as a dumping ground: “I fear still more from the apparent tendency of all persons to use the Float as a good receiver for that which cannot easily be got rid of elsewhere”.His warning was among 15 documents unearthed by a retired engineer, Roger Henley, who was sifting through papers in the archive room at Bristol Port Company as part of his research for a new book about the port. Want the best of The Telegraph direct to your email and WhatsApp? Sign up to our free twice-daily Front Page newsletter and new audio briefings.