Workers from GKN are to lobby MPs as part of their campaign against a takeover of the engineering giant by Melrose.
Members of the Unite union from the South West, West Midlands and South of England, will brief politicians in Westminster on Wednesday.
The union is urging Business Secretary Greg Clark to block the bid, warning that a takeover could lead to GKN being sold off piecemeal and jobs cut or moved abroad.
Unite assistant general secretary Steve Turner said: “There is mounting concern across political parties and business over Melrose’s debt-laden bid and the risk it poses to UK jobs and defence interests.
“GKN will be saddled with over £1.3 billion of debt if Melrose succeeds with its bid, while its advisors will pocket upwards of £140 million in fees. This is a deal that would have ‘The Wolf of Wall Street’ licking his lips and leaves workers fearful that they will ultimately pay for this debt-fuelled bonanza with their jobs.
“Technology and jobs risk being shipped abroad and because of GKN’s defence work our national security is at risk.
“Theresa May’s Government must use its power to block the bid to protect jobs, communities and our national security.”
Unite assistant general secretary for manufacturing Tony Burke added: “GKN is a world class manufacturer. It is essential to the Government’s industrial strategy and is one of the jewels in Britain’s manufacturing crown.
“In Melrose’s hands, all that would be put at risk and ministers’ plans for the UK to be a leader in electric vehicles could be left in tatters.”
A £7.4 billion offer from Melrose, a corporate turnaround company, has been rejected by GKN, which will publish its full-year financial results on Tuesday.
A Melrose spokesman said: “Melrose’s model is about delivering operational improvements, empowering management and investing heavily to unlock potential benefit for all our stakeholders including shareholders, employees, customers and pensioners.
“We do not rely on debt to boost returns, we use only modest levels of leverage and on average we have invested an additional amount equivalent to a third of the original equity purchase price into our businesses to strengthen and grow them through investment in research and development, capital equipment to improve manufacturing efficiencies and bolt-on acquisitions to benefit the businesses.
“We believe that there are no competition or national security issues and that it is in fact in the public interest for Melrose to be the guardian of GKN’s businesses.”