The number of threatening letters received by MPs has more than doubled since 2016, with 101 letters intending to cause distress reported by politicians last year.
In 2016, there were 39 reports of threatening letters received, which rose to 72 in 2017, coinciding with ongoing Brexit negotiations.
Other crimes reported on the parliamentary estate in Westminster are also on the rise, figures from the Metropolitan Police show.
A total of 578 incidents were reported between 2016 and 2018, such as assault, robbery, blackmail and drug possession.
There were 236 crimes were reported last year, including six reports of common assault, two reports of causing actual bodily harm, two reports of cannabis posession and one report of drunk and disorderly behaviour.
This was a 32 per cent rise on the 179 reports filed in 2017, and a 45 per cent increase on 2016, with 163 reports.
In 2017, there was one report of a murder following the death of PC Keith Palmer, who was killed in the Westminster terror attack.
Other notable crimes recorded including one of false imprisonment in 2016, and one report of outraging public decency in 2018.
In March this year, MPs were advised to share taxis home, amid fears of Brexit-related attacks.
In an email, deputy Commons speaker Lindsay Hoyle said black cabs had been arranged by the Serjeant at Arms to collect politicians from the House of Commons, and that police had been put on alert over potential threats to MPs.
In the message, he wrote that he had "never felt this level of tension" during his time in the Commons.
The warning came after Theresa May revealed she was seeking a three-month extension to Article 50.