By 1790, he had set up a business in London with financial backing from well-to-do currier John Maberly, where he designed a new steam engine based on the patented designs of Isaac Mainwaring.
After a long trial, judgement in 1799 was in favour of Boulton and Watt and brought about the collapse of Hornblower and Maberly's business.
In 1803, Hornblower was imprisoned in the King's Bench debtors prison but on his release in 1805 he managed to secure some work in mainland Europe building engines until his return to England in 1813.
Hornblower died on 11 July 1814 and was buried in the Bunhill Fields burial ground in London.
This article about an engineer, inventor or industrial designer from England is a stub.