The deal won the support of 93% of the British defence and aerospace firm's investors at a general meeting, well above the 75% minimum needed for it to pass.
Advent’s offer of 165p per share to delist the business has the backing of Cobham’s board but the aerospace giant’s founding family has tried to block the deal over concerns about national security.
Lady Cobham, the daughter-in-law of Cobham’s founder Sir Alan Cobham, accused the government of “dragging its feet” since the offer emerged in July.
“It would be a national disgrace if this deal is allowed to sail through without any Government intervention,” she told The Daily Mail.
“The government is trading away Britain’s future prosperity and security by failing to protect our defence manufacturing capability.”
Business Secretary Andrea Leadsom has said the government would still be able to open an investigation or block the deal even if shareholders approved it due to Cobham’s extensive military contracts.
A Cobham spokesman said: “The UK has developed a sophisticated system of buying from complex, international supply chains; it has embraced a free and open defence market, where value for money has been a significant consideration for Ministry of Defence procurement decisions, rather than the national identity of the supplier.”
Shares in Cobham rose 1.1% to 161.5p each in afternoon trading.