The National Security and Investment Bill introduces a far-reaching and standalone national security screening regime. It puts in place a mandatory notification obligation for acquisitions of control through the holding of particular thresholds of shares or voting rights in entities in the most sensitive sectors of the economy. It also specifies a voluntary regime for a range of other transactions where control is acquired at an asset level. The hybrid notification regime is accompanied by an expansive “call-in” power to enable the Government to review non-notified transactions up to five years post-completion and the power to impose serious sanctions for non-compliance. The Bill represents a radical upgrade of the UK foreign investment regime.