I think you\’ll find that this was predicted:
According to Romanians who have worked in Britain, many who exercise their right as EU citizens to enter the country simply disappear into the black economy. Others sidestep the regulations by seeking self-employed status or by securing a contract with a British firm.
Daniela Marinescu, who runs the Phoenix recruitment agency from an office in a concrete block near the centre of Bucharest, said the rules simply pushed those who wanted to work in Britain underground. "Most people who want to go to the UK will go there to find jobs on the black market," she said.
All that happened, following the denial of the right to work, but with the right to enter as EU citizens, was that people entered and worked illegally. Such a victory for those wanting immigration curbed, eh?