Gorgo

 

 (wikipedia)

GORGO-1961-Two guys Ryan (Bill Travers; later in BORN FREE) & Slade (William Sylvester; later in DEVIL DOLL) heading a cargo ship discover a prehistoric lizard monster off the Irish coast. They bring it back to London where promoter Dorkin (Martin Benson) exhibits him/it. Some scientists determine that Gorgo is not full grown and a parent could be on the prowl. Sure enough Mama comes looking for her baby, destroying most of London in the process (including Big Ben). 

There's basically no women in this movie! 

Director Eugene Lourie was no stranger to giant monster having directed both THE BEAST FROM 20,000 FATHOMS and THE GIANT BEHEMOTH. Interesting UK production with an unusual ending.