Theresa May heads to a summit for European leaders on Thursday with the possibility of Britain having to pay a hefty fine imposed by an EU watchdog.
The Office Européen de Lutte Antifraude (OLAF) is accusing the UK of being liable for illegal Chinese goods flooding black markets on the European mainland.
They could potentially impose a fine of between £1.7 billion to compensate for this. A spokesperson for the Prime Minister made it clear the UK does not recognise this fine.
The prospect of OLAF's fine hangs heavy over Theresa May as she flies to Brussels for what could be her last European summit before Article 50 is triggered and exit procedures begin.
In the end, the European Commission will decide whether there is weight to the accusation made by OLAF, and choose to impose the fine.
If they do, it could become a new battleground between Britain and EU authorities, potentially increasing the tension in the upcoming Brexit negotiations.