This is the "benefit tourism" notion: that poor eastern Europeans will move to the UK to live off the state, claiming unemployment pay, social housing, and other benefits that should be reserved for British workers. Even Cameron has had to admit there is no "quantitative evidence" this phenomenon exists. Nevertheless, he talks about it constantly, as if it did.
The whole thing is a charade and these "new" restrictions on immigrants don't change a thing. New immigrants already had to wait three months to access unemployment benefits and it is illegal for Britain to charge EU citizens for medical care. The Conservative Party has just been churning out fake solutions to phantom problems.
It is doing so to ward off the challenge from its emerging far-right rival, the anti-EU, anti-immigrant United Kingdom Independence Party, which has been poaching alarming numbers of right-wing Conservative voters. With an election due next year, Cameron is running scared, and has got into a "nastier-than-thou" bidding war with UKIP.
The anti-immigrant voters Cameron is pandering to will not change their minds when the predicted tidal wave of Balkan immigrants does not happen, nor will he change his story. He will claim his emergency measures stopped it. But this tempest in a teapot highlights the sheer power of the principle of free movement within the European Union. It is what makes EU citizenship the gold standard in terms of passports.
Like the US and the Canadian province of Quebec, several EU countries offer fast-track residence permits to foreigners who invest a large sum in the local economy: from US$400,000 ($481,300) in Greece to 9 million ($17.8 million) in the UK. But they still must live in the country in question for up to five years before getting their citizenship and passport, and the average jet-setter wants more for his money.
A US passport is no longer so desirable because US tax and reporting requirements apply to its citizens no matter where they live, and many countries impose tit-for-tat visa requirements in response to US border controls. Moreover, it's getting easier to obtain an EU passport.
Last November Malta, the smallest EU member, announced a programme that skips the residence requirement and sells passports to "high-value" individuals willing to pay the Government 650,000 ($1,061,000). It's a quite reasonable price for a passport that confers the right to live and work almost anywhere in Europe and also offers a visa waiver for travel to the US.
Maltese patriots were horrified but then mollified when the Government raised the price to 1.15 million recently.
So now we know the real value of an EU passport.
Who buys them? Mostly rich Chinese: 248 out of 318 residence permits issued by Lisbon in the past three months to people who invested 500,000 in Portuguese property went to Chinese nationals.
Nor is there a shortage of potential customers: a Bank of China survey revealed almost half of Chinese citizens with assets worth more than 10 million ($1.9 million) are considering moving abroad.
Any EU passport - Portuguese, Latvian, Irish, whatever - gives its holder the right to live anywhere, work anywhere, set up a business anywhere in a community of 28 countries with a total population of 500 million-plus. The principle of free movement makes it so valuable and no amount of protest by "Little Englanders" on the right of British politics will change that.
Gwynne Dyer is an independent journalist published in 45 countries.