Could someone answer this for me please: A mate has 2 kids to his ex wife, they are 4 or 5 years old I think. He pays her £250 per month cash. He's now making noises about marrying his new bird and his ex has started to go all radge - asking for more money and threatening him with the "I'll go to the CSA and get you cleaned out" routine out of vindictivness. He earns between £900 and £1050 a month. Would it be worth his while just going to the CSA himself and getting it all above board or would they demand back payment for however long it's been since they split up etc? From what I gather she's claiming benefits, don't know which ones exactly but I always thought she would have to declare who the father was and explain what was being paid etc?? He is apparently named on their birth certs. Would it be good advice to tell him to call her bluff and contact the CSA himself and what sort of monthly payment could he get stung with? Cheers. And no - It's not me, it is actually a mate. I don't have kids and have been happily married for a while now Edit> She always insisted on the money paid cash to her and apparently point blank refused when he suggested setting up a standing order thingy. I understand that in the eyes of the law he has never paid anything-based on that???