Here we go:
chemed.chem.purdue.edu...
The decision was made{by people from the manhattan project] to develop the weapon, and the first artificial fusion reaction occurred when the hydrogen bomb was tested in November 1952.
Here is an article on the history of it
www.tab.fzk.de...
Here is one that might provide an answer
www.fusion.org.uk...
The original large-scale experimental fusion device on which British physicists worked during the 1940s and 50s was housed in a hangar at Harwell
Tho on second thought that appears to be strictly britian.

