The government is to review Altice’s growing stake in BT on grounds of national security.
In a statement to the Stock Exchange BT said business secretary Kwasi Kwarteng was to exercise his “call-in power” under the National Security and Investment Act 2021, adding that it would co-operate with any investigation.
Last December, Altice, controlled by the French-Israeli billionaire Patrick Drahi, raised its shareholding in from 12% to 18%.
At the time Drahi said he did not intend to make an offer for BT and has “engaged constructively” with the board and the telco’s management.
Under the National Security and Investment Act 2021, the Secretary of State for Business has the power to either approve Drahi’s investment outright, impose certain conditions, or block it completely.
The Act also allows the Government to halt a single investor from owning more than 25% in a business deemed to be of national significance.
Altice owns to French mobile company SFR and also holds interests in Portugal and the United States.
Shares in BT fell by 5% in early trading.