The prospective withdrawal of the United Kingdom (UK) from the European Union (EU) – so-called Brexit – is expected to have a significant impact on the social security arrangements for mobile employees. There is currently no detail on what the arrangements will look like for new post-Brexit assignments; stakeholders are waiting to see whether new arrangements will be made, or whether the UK and Europe will default back to the old bilateral agreements between them. However, transitional arrangements pursuant to the new draft Withdrawal Agreement released by the European Commission will apply to those employees on assignments that start prior to 1 January, 2021.