Summary The UK’s long-awaited National Security and Investment Act passed into law on 29 April 2021 when it received Royal Assent. Secondary legislation will follow and the regime is expected to be fully in force towards the end of the year. Here is what you need to know… The National Security and Investment Act 2021: The UK’s long-awaited National Security and Investment Act passed into law on 29 April 2021 when it received Royal Assent. Secondary legislation will follow and the regime is expected to be fully in force towards the end of the year. Although the Act is not live yet, investors should already be considering its possible impacts on deals because of the retrospective effect of the legislation, the Secretary of State’s broad powers under it to “call-in” non-notified transactions for review, and the sanctions for non-compliance (for more detail on this, see our earlier blog post 'UK National Security & Investment Bill introduces mandatory Government review of a wide range of transactions').