James Phillips, 46, pleaded guilty to malicious communications at Westminster Magistrates’ Court on Wednesday, 7 February.
The office of Finchley and Golders Green MP Mr Freer received three calls on January 31, two of which were “heavy breathing” and the third was a “man with a London accent”, Adrita Ahmed, prosecuting, said.
The caller said: “I’m coming for you, you c***, not just Mike Freer but you as well,” Ms Ahmed told the court.
Officers carried out a number of enquiries which resulted in Phillips being identified as the person who had made this call. He was arrested on Tuesday, 6 February.
Detective Superintendent Will Lexton-Jones, from the local policing team in north-west London, said: “This incident was first reported to us less than a week ago. Officers carried out urgent enquiries to identify and locate the suspect and detectives have worked tirelessly to secure charges.
“This conviction demonstrates how seriously we treat threats and abuse towards MPs and other public officials.”
Phillips also pleaded guilty to assaulting an emergency worker after he attempted to strike an officer while he was in custody. He will be sentenced at the same court on Wednesday, 6 March.
It comes after Mr Freer – the Tory MP for London’s Finchley and Golders Green seat since 2010 – said it was time to say “enough” as he could no longer put his family through fears for his safety.
The minister, who has pro-Israel views and represents a heavily Jewish constituency, said antisemitism was behind some of the intimidation and attacks on his office.
In December, his constituency office was subject to an arson attack. The fire was understood to have started in a shed behind the building. It destroyed the shed and part of the first, second and third floors of the property.