Improving the educational standards of British youngsters is vital to controlling immigration, David Cameron has said.
The prime minister said immigrants could not be blamed for seeking jobs in British factories when schools and colleges were not producing students with the required skills to do the work.
He said in some plants half the work was done by migrants from Eastern Europe. "You can go to factories in our country where half the people come from Poland, Lithuania or Latvia," Cameron said. "You can't blame them, they want to work, they see the jobs, they come over and they do them.
"But as a country what we ought to be saying is 'No, let's get our education system right so we are producing young people out of our schools and colleges who are fully capable of doing those jobs'."
The welfare system required reform so it "does not pay to be out of work" and immigration needed to be restricted, he added.
"Let's have sensible controls on immigration, particularly from outside the EU where we can cap the number of people who come," he said.
Linking education, welfare reform and immigration, he said: "Crack those three problems together and we can really get an economy that generates wealth for our people."
Speaking at Oxford's Mini plant at an event celebrating apprentices, Cameron defended the Government's controversial work experience programme.
He said: "Getting people into the workplace, giving them experience of work, of timekeeping and all the things it means to have a job is a really good way to help get people started.
"It's a cruel fact but it's true that the best way to get a job is to have one already."
He added: "The danger for a country like Britain is yes, you see the economy recover, yes you see jobs coming, but you leave behind people who have not got the right qualifications from school. I don't want that to happen in our country."