Most people stop at two, a few brave souls go on to have three or four. The average British family now has 1.9 children and that number is steadily decreasing. But when it comes to having kids, there are a handful of families who are bucking the trend. This new three-part series explores the lives of some of the UK's biggest families. What makes some families decide to have 3, 4 or even 15 children? And how do both the parents and children cope when even the school run or a simple trip to the supermarket has to be run like a military-style operation.