If your ancestor was a civil or mechanical engineer then the latest archive on Ancestry.co.uk will certainly be of interest. The records of the Institute of Mechanical Engineers (IMechE) and the Institution of Civil Engineers (ICE) contain details of over 100,000 people between 1830 and 1930 who built and shaped their world and left a lasting legacy for modern Britain.
Many of them were the greatest engineers of the Victorian era: pioneers of automobiles, construction techniques, mechanics, and all types of technology. Famous names in the records include Isambard Kingdom Brunel, Sir John Rennie, Christopher Hinton and Sir F Henry Royce.
The collection comprises membership records and photographs of engineers who were members of both institutions between 1820 and 1930. It is in three datasets, one of which includes photographs of the individual members.
UK, Civil Engineer Photographs, 1829-1923
UK, Civil Engineer Records, 1820-1930
UK, Mechanical Engineer Records, 1870-1930
There is one search page for all three datasets.