Sheriff Craig McSherry said that EU nationals have to be treated as first offenders because of the near-impossible task of obtaining offending histories from authorities in their home countries.
Politicians and campaigners have called for an improvement in checks in the wake of a string of cases involving violent foreign criminals.
They include former Red Army soldier Vitas Plytnykas, the “head on the beach” murderer, who butchered fellow Lithuanian migrant worker Jolanta Bledaite in Brechin, Angus, in 2008.
It later emerged that Plytnykas, jailed for life with accomplice Aleksandras Skirda, also Lithuanian, had been in prison in Germany for a drug-related killing.
Another high-profile foreign criminal with a litany of previous offences in his home country was Marek Harcar, who abducted, raped and murdered businesswoman Moira Jones in Queen’s Park, Glasgow, in 2008.
Harcar, a Slovakian, had 13 previous convictions, four of them for violence.
Criminals can enter Britain unchecked due to EU freedom of movement rules. The same rules prevent EU criminals being deported after a sentence of less than two years.
Tory chief whip John Lamont said: “Given the information sharing across the EU, I find it almost unbelievable that this difficulty should exist.