Cities minister Greg Clark wrote to voting watchdogs expressing concerns Tower Hamlets residents would be too fearful of reporting to the police evidence of electoral malpractice, for fear their names would be disclosed to the London borough.
A Freedom of Information request has revealed that Mr Clark, who was appointed minister for universities, science and cities in the August reshuffle, wrote to Jenny Watson, chair of the Electoral Commission, in the aftermath of the 22 May local elections.
In a letter dated 30 May, when he was still Cabinet Office minister for the constitution, Mr Clark voiced his concerns about the process that saw controversial Mayor Lutfur Rahman re-elected to the top political post at the East London borough.