The Marriage Act of 1949 states that Weddings can only be held in a "permanent and identifiable place'' - so just how have hundreds of couples been able to hop of board as singletons and jump off as husband and wife?
The trick lies in where the ship is registered.
Ships bosses were quick to realise that many couples would want to get married at sea but would be unable to do so under current British law. With this in mind, many cruise ships have had their registration switched away from Britain to accomodate - the latest being P&O liner 'Orianna'.
Pressure is mounting on the governement to change the rules, but no law update is likely in the near future. But thanks to some smart thinking bosses in the cruise industry, at least some couples will be able to tie more than a sailor's knot when they're out at sea!