This article considers the types of M&A deals that the UK government has intervened in using its powers under the National Security and Investment Act (NSIA) and the conditions that have been attached to secure approval. It further considers the global position of the UK by comparison to similar regimes that regulate foreign investment in other jurisdictions (such as CFIUS in the US) and the potential issues faced by multi-national investors needing to grapple with multiple sets of rules.