Queen Mary II?

Question

Why the Q.M II has been built in St.Nazaire ?

Answer 1

Several reasons, not the least of which is because there wasn't a yard in the UK that had the capability to build a ship the size of QM2.

John Brown which built many of Cunard's liners including QE2 is no longer in business, nor was it large enough to build a ship as large as QM2.  

There aren't many yards that can build a ship the size of QM2.  Meyr-Werft probably could have, Aker Yards in Turku, and some of Fincantieri's yards probably could have done it.

BTW...  Cunard's liners don't use Roman numerals as part of the name.   Roman numerals are reserved for royalty.  The actual Queen gets a II, but the ship gets a 2.