MP Mark Lancaster is to stand down at the general election, citing death threats and abuse.
The 49-year-old Conservative member for Milton Keynes North has served his constituency since 2005.
The defence minister said the current levels of anger endured by elected representatives "is not the politics we want or need for our great country".
"After much soul searching, I have decided that now is the time for me to stand down", he said.
'Not easy decision'
"Like so many others I have fallen in love, not only with the place but the wonderful people, from all walks of life, that make Milton Keynes one of the best places to live, work and play in our great country."
It was not an easy decision to make, and "now is the right time to seek new challenges" he said.
Mr Lancaster, who is a colonel in the Royal Engineers said: "The politics of today, with all its anger, abuse and in my own case, two threats on my life, is not the politics we want or need for our great country.
"We have always been at our best and delivered the most, when we are able to express political disagreements through healthy debate then unite as a community and as a country.
"I hope one day that we can return to such a place", he added.