Staff at the UK's largest microchip factory have urged the business secretary to U-turn on his decision to force its Chinese owners to sell a majority stake.
Grant Shapps revealed last week that Nexperia must sell at least 86% of its interest in Newport Wafer Fab because of national security concerns.
The plant, which produces transistor-style chips that are commonly found in things like charging cables and hairdryers, employs almost 600 workers.
Its staff association used a letter to Mr Shapps on Monday to argue that their livelihoods had been placed at risk by the ruling.
The letter said: "We are in disbelief that you have decided to order Nexperia to sell their semiconductor factory in Newport.
"We are also angry that your decision might imply that a member of our team may, in some obscure way, undermine the UK's national security.
"This is beyond contempt".
The letter went on to describe Nexperia as good employers who had invested heavily in the factory.
The signatories urged Mr Shapps to visit the plant to see that work for himself.
They also claimed that no international company would want to invest in the UK in the wake of the decision.
The letter's sentiments were echoed in the Commons by Labour's MP for Newport West, Ruth Jones.
Responding to an urgent question on the sale, Mr Shapps said: "She's not privy to the information that I have had to weigh up in order to come to this national security decision, which I have done with the upmost diligence and taking all of the factors into account."
Nexperia, which is Chinese owned but based in the Netherlands, has warned that any forced sale risks job losses and said that it plans to appeal.
It said last week: "The far-reaching remedies which Nexperia offered to fully address the government's concerns have been entirely ignored.
"The UK government chose not to enter into a meaningful dialogue with Nexperia or even visit the Newport site.
"More than 500 employees in Newport also raised their own significant concerns about such a divestment - the government has chosen not to listen to them and instead taken this decision which puts the livelihoods of them and their families, as well as more than £100m of taxpayers' money, completely unnecessarily at risk."
Authorities in Beijing also reacted with anger.
A Chinese foreign ministry spokesperson said on Friday it resolutely opposed the ruling and added: "The British side should earnestly respect the legitimate rights and interests of Chinese enterprises, and provide a fair and non-discriminatory business environment for enterprises of all countries."