Ukraine and Russia are locked in ongoing negotiations over the future of Russian gas transit into Europe via Ukraine. The existing transit and supply contracts expire at 10 am on 1 January (Moscow time). If the two sides fail to reach an agreement, Europe will wake up to a new decade wrestling with gas shortages in the middle of winter – the severity of which will depend on several factors. We explore three possible disruption scenarios to provide a range of price implications for Northwest European markets. Europe has a range of levers to help bring the gas market back towards balance. Some will need to be pulled more than others, with the consequences stretching well beyond European borders. But it is Central and Eastern European markets along with Ukraine itself who will suffer most from any disruption.