Dave Lewis warned the food giant faced potential hardship securing temporary labour once the UK had divorced from the Brussels bloc.
He has now called on the government to provide assurance for Tesco’s supply base before the two-year negotiations have finished in 2019.
Speaking to ITV, Mr Lewis said: “Like everybody, we too want certainty, we employ 325,000 colleagues here in the UK.
Tesco cheif Dave Lewis warned of post-Brexit supplier issues
Our concern is actually for our supply base
Dave Lewis, Tesco CEO
“It’s a very rich and diverse group of colleagues, we don’t expect anything to affect our colleagues inside our retail business.
“Our concern is actually for our supply base, that does require some temporary labour to help with crop picking and so there’s a little more uncertainty in that base.”
Dave Lewis insisted Brexit would have no impact on retail staff
The prime minister argued an “implementation period” may be necessary depending on the “nature of the deal”.
The European Council president Donald Tusk has already made clear the bloc’s “core principles”, including freedom of movement, must be maintained during any transitional arrangement.
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Speaking on a recent trip to the Middle East to boost Brexit support, Mrs May said: “If you think about it, once we’ve got the deal, once we’ve agreed what the new relationship will be for the future, it will be necessary for there to be a period of time when businesses and governments are adjusting systems and so forth, depending on the nature of the deal, a period of time during which that deal will be implemented.”
Theresa May hinted of a possible "implementation period" post-Brexit
The Prime Minister’s message has been echoed by Christine Lagarde, who has predicted Britain will remain a “transitional” member of the EU after the two-year Brexit negotiations.
The International Monetary Fund President said it was a “sensible approach” for both parties to take in the historic European divorce.
She told Bloomberg: “I understand that probably the parties will be heading towards a traditional period.
“Which to me is probably a sensible approach, given the complexity of the task and the many issues that need to be addressed, tackled and resolved.
“There are multiple issues – whether it’s trade, financial sector, individual situation of migrant workers or the border between Ireland and Ireland.”