Evtec supplies parts to JLR and chairman David Roberts said it was a “worrying time”.
“A lot of the jobs here, if they go, they go, they leave the sector,” he said.
“And these are jobs with real skills that take years to build and it’s easier to lose them.”
JLR has been dealing with falling sales, the consequences of a devastating cyber-attack that paralysed production last year, competition from China and rising energy prices.
At the same time, it has invested billions in an effort to reinvent itself for an electric future.
Dr Steve McCabe, a political economist from Birmingham City University, said he believed the job cuts were a strategic move.
“What JLR are trying to do is clean themselves up and make themselves more efficient in the hope that alowes them to survive,” he said.
“The hope is of course that its a temporary thing,” he added.
The company’s reinvention is due to take another step forward when it unveils a new electric car on 6 October.
Kevin Moreley, a former managing director of the Rover Group believes it could be a pivotal moment.
He said: “I always thought that only 300 redundancies for JLR was a little optimistic given the new Jaguar launch is still unpredictable, and VW are making 100,000 workers redundant.
“4,000 will not be the end of it if the new Jaguar doesn’t sell the numbers they hope.”
