David Cameron has praised Ellesmere Port Vauxhall as a ‘success story’ for the country.
He said a vote to pull out of Europe would be a ‘leap in the dark’.
The UK will decide whether it wants to stay in or leave the EU in a referendum on June 23.
The PM told Vauxhall employees: “The British car industry is doing well, it’s a success story built on a strong workforce.
“Companies also know if they come here to Britain they will get access to the single market.
“So congratulations, you are a success. I hope we vote to stay in the EU and we will continue to see success in the automotive industry, not least here in Ellesmere Port.”
High-profile Conservative MPs Boris Johnson, Michael Gove and Chris Grayling have all sided with the leave campaign as the party splits on the issue.
They believe renegotiating trade deals with Europe and the rest of the world would be possible before the agreements would expire two years after the potential departure from the EU.
'We need to be clear'
Mr Cameron said those who were supporting a 'Brexit' could not say what would replace the UK’s access to the single trade market and accused them ‘lacking specifics’ on the issue.
He said: “We need to be clear.
“If we voted to leave, we could sign the best possible free trade agreement in the world with the EU.
“But it still would not come close to giving British companies the access they get to the world’s largest free trade area from the single market.”
Eurosceptics have said the Prime Minister's recent renegotiation of the country’s deal with Brussels did not go far enough and leaving the EU would help the UK take back its sovereignty.
Mr Johnson has said it is a ‘political project’ that was in ‘real danger of getting out of proper democratic control’.
A recent poll suggests Vauxhall Motors, who employ more than 2,000 staff in Ellesmere Port, and other motor manufacturers say Britain should remain in the Europe.
The PM took a tour of the plant and also spoke about the need to protect jobs in other industries across the North West.
At Prime Minister’s Questions earlier this week Mr Cameron said he would not resign if his side lost the referendum.
In Ellesmere Port he also shrugged off questions about the Queen’s own position on the EU.
All four of Cheshire West MPs , two of which are Conservative, have said they will vote to remain.
Mr Cameron said: “For those who advocate leaving, lost jobs and a dented economy might be worth collateral damage, or a price worth paying.
“For me they’re not. They never are.
“Because there’s nothing more important than protecting people’s financial security.”
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