The government is to outlaw the use by companies of covert blacklists that have prevented trade unionists from getting work…Blacklisting re-emerged as a political issue in March when the information commissioner, Richard Thomas, closed down a private investigator who had compiled an "extensive intelligence database" of 3,000 workers. Thomas accused 40 construction firms of buying personal data about workers they wanted to vet before employing them…The government was criticised for passing a law banning blacklisting in 1999 but then deciding not to take the last step of enforcing that law.