Burt, who has worked closely with the construction industry in implementing the Egan reforms in government departments, will leave the Treasury at the end of May.
He will become chief executive of European Career Systems, a joint venture between the Public Sector Information Group, an independent publisher of government information, and Cityjobs, an on-line recruiter.
European Career Systems will provide a recruitment service for the public sector.
Burt, who has been with the civil service for 27 years, was well thought of in construction.
Cain was unavailable for comment but a spokesperson said he would continue in his current role until the end of December.