Francois, The passenger lists on www.ancestry.co.uk start in 1878. However what are described as 'Alien arrivals' into England for the years 1810-1811, and 1826-1869, do show one person with the surname THIAULT. Unfortunately my subscription does not permit me to view the details. As per other comments, it would be easy for you to purchase the pay-to-view credits. I presume that it is Gustave Thiault whom you are looking for? A Mr. Thiault left Southampton on 24th August 1843 on the P&O steamer Bentinck and arrived in Calcutta on 18th November 1843. This may have been Gustave? There are several entries on the FIBS web-site relating to him. And looks like one on the familysearchbeta site where it refers to Gustave as 'C. L. G. Thiault.' Noel