Presumably, it means that the government has focused on no foreigners as the bottom line for their Brexit deal. They might accept the single market, and presumably they are being pressured to do this by business and the City, but definitely no nasty Poles and French people. Well, I don't know, but neither does anybody else.
Also, there may be exemptions for some areas such as agriculture, so that E. Europeans can still be employed for those nasty 6am shifts.