Both Marina + the Diamonds and Passenger have had huge global success, but which act will rule the British Isles within our Battle of the Brits?

Marina + the Diamonds is a forced to be reckoned with, as she's had quite the degree of success since the release of her debut EP 'Mermaid vs. Sailor' in 2007. In the past six years, she won an MTV EMA for Best UK & Irish Act and had both of her full-length albums hit the Top 5 on the U.K. charts. Marina + the Diamonds' 2012 album 'Electra Heart' actually debuted at No.1!

Passenger, aka Mike Rosenberg, has also found quite a bit of success on a global scale. The folky singer-songwriter originally began in a group called Passenger, but continued as a solo artist under the same name. His track 'Let Her Go,' off his latest album 'All the Little Lights,' has hit No. 1 in 16 different countries and has been certified platinum in six of those.

Who will you vote to win -- Marina + the Diamonds or Passenger? You can vote for your favorite below once per hour until the poll closes on July 31 at 2PM ET!