The government has approved a US private equity firm’s takeover of UK defence and aerospace company Cobham.
Advent International made a £4bn offer to buy Cobham in July and shareholders approved the deal in August.
A government report found the merger caused some national security risks, but said on Friday concerns had been mitigated to an “acceptable level”.
The founding family of the firm said the announcement on Friday evening was “cynically timed to avoid scrutiny”.
Cobham, which employs 10,000 people, has extensive contracts with the British military and is seen as a world leader in air-to-air refuelling technology.
The firm, based in Wimborne, Dorset, also makes electronic warfare systems and communications for military vehicles.
Its expertise played a significant role in the Falklands War, allowing the Royal Air Force to attack the remote Port Stanley airfield.
Defence experts said its role in air-to-air refuelling was essential for modern warfare and could raise national security issues if the company was sold.
In September the government intervened in the takeover, citing national security concerns.
But in a statement on Friday, Business Secretary Andrea Leadsom said she was satisfied the risks that had been identified had been mitigated “to an acceptable level” – and allowed the deal to go ahead.
Mrs Leadsom said the decision had been “meticulously thought over” and came after she took advice from the defence secretary and the deputy national security adviser.