There will be more jobs
Less people in the country, fewer jobs to do - so not exactly.
Result: Neither
There is a myth that "Immigrants take British jobs from British people" (source).
Unfortunately it's not that simple, as there isn't a fixed number of jobs in the country.
The more more people here, the more demand for goods and services.
You could argue that some low paying jobs will be effected, but farming/nursing/hospitality are already having difficulty finding employees that are willing to work for low pay, which suggests that wages might go up.
If you disagree, or would like to add more details, please let me know.
You can suggest a reason for leaving the EU, or look at the other reasons.