Bute East Dock, Cardiff was the second dock opened by Lord Bute, in stages from 1855 to 1859. The dock was entered from the sea by a two gate lock, where there was a basin and a further lock to enter the main dock. 45 acres of water were enclosed and fifteen coal staiths erected, allowing 1 million tons of coal a year to be handled at this dock alone. By 1890 there were 30 staiths, plus three ballast cranes and 22 hydraulic cranes. The only original building fronting the dock to survive is the Bute Warehouse. The basin and entrance to the dock (the current site of the Senedd Building, NPRN 403909) has been filled in and a crane relocated cosmetically on the east side.

(A Guide to the Industrial Archaeology of South East Wales, AIA, 2003)
B.A.Malaws, RCAHMW, 21 March 2005.

What remains of the original body of the dock now forms a central feature of Atlantic Warf.
A.N. Coward, RCAHMW, 16.05.2019