Seen the YouTube wedding clip where, mid-ceremony, the ring-bearer trips and pushes the bride into a swimming pool? Worst. Don't worry - this is not going to happen to you. But, given the amount of detail that goes into a wedding, it's inevitable that some things will go awry on your big day. Here are the most common 'Oh no!' scenarios, and advice on what to do (we promise your guests won't know the difference).