Worth, who replaced George Bridges in a leadership role at the Huntsworth-owned public affairs firm less than a year ago, is understood to have handed in his resignation to launch what will be named The Westminster Policy Institute.
He declined to comment on the new venture but according to one source it will involve a small team with a focus on giving policy, rather than public affairs, insight.
It is likely to by launched by September with a view to party manifestos being developed ahead of the 2015 general election, the source added, stating:
"Sean is looking at creating something that’s a cross between a think-tank and a research institute. There’s a real lack of ideas coming from businesses and the public sector when it comes to some of the big problems being faced by the Government and his consultancy will look to inform that debate."
Worth left his role as the Prime Minister’s special adviser in June 2012 and went on to join MHP before being snared by Quiller last October.