Shropshire MP Mark Pritchard has quit a top Conservative Party post in a protest over government policies on Europe and immigration.
The Wrekin MP resigned as deputy chairman of the Conservative Party International Office claiming the EU was hurting businesses in the county.
In his resignation letter to David Cameron, Mr Pritchard said he was concerned about an increasing number of Government policies "not least on immigration, Europe, and a lack of clarity for national and individual aspiration".
And he said that remaining in the post would "inhibit my ability to speak out more freely on these and other issues".
Mr Cameron appointed Mr Pritchard to the position, which promotes democracy in developing countries, in 2010. Downing Street today declined to comment.
But a Conservative Party spokesman today said: "Mark Pritchard is well known for his forthright views."
In a statement Mr Pritchard said the Conservatives needed to be far more robust on Europe.
He said: "The EU is eroding our independence as a nation, costing jobs, increasing taxes, and hurting businesses in Shropshire."
Mr Pritchard also announced he would not stand for re-election as the secretary of the powerful backbench Tory 1922 Committee.