Ford has been accused of a "scandalous lack of corporate social responsibility" by a leading Welsh economist over the way it has handled the plan to close its Bridgend plant.
Kevin Morgan criticised Ford for not informing First Minister Mark Drakeford until hours before the workforce was told.
Ford said informing employees first of any major decisions was its priority.
The engine plant will shut in 2020 with the loss of 1,700 jobs.
"Our priority is to always try to inform our employees first of any major decisions that impact them. They are always our priority," a Ford spokesman said.
Prof Morgan, professor of governance and development at Cardiff University, added: "What does Welsh Government do now about re-equipping that workforce with alternative forms of employment?
"We'll need to be more agile than we've been in 20 years of devolution".
Ford said it would still have gone ahead with the proposed closure in the absence of the Brexit issue, but added "we have consistently stated that a no deal, hard Brexit would be catastrophic for our operations and for much of the auto industry in the UK".
But Mr Jones told BBC Radio Wales' Sunday Supplement that closure was "never on the agenda" for Ford and "nobody anticipated" it.
"It seems to me that the decision was taken a week or a fortnight before the announcement, so it was something very quick, something changed in that time for them to move to a position where they proposed closure.
"I know they said publicly Brexit wasn't a factor, but that's not what they told the [Economy and Transport] Minister Ken Skates.
"Brexit was not a dominant factor, there are other reasons of course, but nevertheless it was a factor and they went into detail why it was definitely a factor."
Responding to Mr Jones' comments, Welsh Secretary Alun Cairns said the UK Government had voted to "bring about stability in every possible stage of the Brexit negotiations".
He said that although "certainty on Brexit is important to the economy and the manufacturing sector", Ford had been "explicit" that Brexit was not part of the decision to close the Bridgend factory.
"If they were going to manufacture in Europe instead of moving their plant to Mexico, then there would be more credibility to the question around the role Brexit has played here," he said.
Carwyn Jones also said many businesses had told him in private they too had concerns, but few were willing to take a public stance on the issue.
"They get very nervous about saying something they think might upset the UK government," he said.
"They are reluctant to commit to a particular viewpoint in public."
Mr Jones, who is also the AM for Bridgend, said the "sheer magnitude" of the size of the plant and the number of people it employed meant the town and surrounding areas would struggle to "absorb" the number of people unemployed.
"Bridgend unemployment is very low, in the past it's been able to absorb any job losses relatively easily but not of this number.
"[The employees] are not all from Bridgend so effectively this will be felt more widely too."
He said it was difficult to imagine another company being able to take on the plant due to its size, adding the former Sony manufacturing site in Bridgend had been divided into sections so this may be a possibility.
"When it was built [Ford] was the largest factory in Europe under one roof, it's too large for almost any company."
But he added: "I've still not given up.
"I'm still going to fight hard for my constituents. Let's not pretend it's not an uphill battle because it is, then let's see what uses might be made of that building."