Decommissioning is arguably the single biggest issue in the minds of those interested in UK oil and gas right now, weighing on operators, oilfield services companies, prospective asset buyers and sellers. In total, Wood Mackenzie estimates future decommissioning spend from 2017 onwards at £53 billion (US$66 billion, 2016 terms) with £11 billion (US$19 billion) expected to be spent over the next five years. There are a number of uncertainties surrounding this market, from fundamental questions such as how much will it cost, when will it happen, through to what happens if someone defaults on their liabilities. There are, mercifully, some certainties in the decommissioning sector. The UK has stringent regulations that set out the obligations of what needs to be removed, how to handle companies defaulting on obligations and decommissioning relief deeds (DRD) which guarantee the rate of tax relief.