I was wondering if anyone has this issue: ex-partner working under a tax-dodging scheme- being paid by an off-shore agency whilst residing and working in the UK often for a UK-based firm? The practice is really common with construction contractors and is surprisingly not illegal. The problem comes when the CSA seek to do a calculation. If the parent without care denies they are working, the CSA cannot investigate because there are no tax details and if they are technically working for a company outside the UK they do not have jurisdiction and have to enter a nil assessment. The CSA cannot investigate bank accounts without proof that the parent without care is living a lifestyle incompatible with their not working - a difficult thing to prove. Is anyone in this situation? I am resolved to raise awareness about this and prevent it happening to other children. Any advice/ experiences/ thoughts welcomed :)