Vauxhall has reopened production at its Luton plant after the government loosened restrictions imposed to tackle the coronavirus pandemic.
Managing Director Stephen Norman said 800 out of 1,600 staff returned to the factory, which produces vans, on Monday.
It comes on the same day Ford re-opened its engine plant in Wales.
Mr Norman said Vauxhall would be going beyond government guidelines to ensure staff safety.
He said all staff have had to take their temperature, morning and evening, for the past 14 days.
“We will also take temperatures with an infrared sensor as people come in and social distancing is observed throughout the plant,” he added.
Mr Norman said 150 production operations previously requiring less than two metre distancing have been reduced to “less than 50” and in those cases “we provide extra PPE”.
Groupe PSA, Vauxhall’s parent company, employs about 5,500 people in the UK, 90% of whom had been placed in the government’s furlough scheme.
The company’s Ellesmere Port plant, which makes cars, remains closed.
Mr Norman said Vauxhall will be able to bring more staff back when car showrooms re-open in the UK.
The government has suggested that will happen from the beginning of June, depending on how the spread of Covid-19 progresses.
Vauxhall has been lobbying the government to bring that date forward.
Mr Norman said the company had lost 95% of its market due to the lockdown.
“No company could survive that without the furlough arrangements and this re-start itself.
“We must not forget the human element of this. The motor industry is a gregarious place. People don’t join it to isolate themselves.”
Ford’s 1,200 strong workforce in Bridgend also returned to work having been on furlough since 25 March.