The government is to intervene in a US private equity firm's takeover of UK defence and aerospace firm Cobham, citing national security concerns.
Advent International made a £4bn offer to buy Cobham in July and shareholders approved the deal last month.
But Cobham's founding family raised concerns about the company's future and its connections with UK defence.
The government said it wanted to "support private sector innovation whilst safeguarding public interest".
Advent International and other American firms have clear ties to the US Government and cannot be allowed access to any of the UK's vital infrastructure or the opportunity to steal British intellectual property.