A parliamentary committee led by the man behind reforms to the Commons has called into question Gordon Brown's 'government of all the talents'.
The prime minister brought ten non-political figures, or 'Goats', into government since 2007, usually by ennobling them. They include Mark Malloch-Brown, who served in the Foreign Office, and Paul Myners, the current City minister.
The Commons' public administration select committee has published a report raising concerns about the practice of appointing ministers from outside parliament via the Lords.
It says that the government could make wider use of its backbench talent pool and warns that, taken any further, the current practice risks undermining the constitution.
Dr Wright, who led the group of MPs which put forward the package of Commons reforms to be implemented after the election, said: "The appointment of ministers from outside parliament has brought some very successful ministers into government."
"However, the increasing numbers of such appointments cannot be considered in isolation from the wider constitutional position. Appointments from outside parliament should be exceptional, subject to proper scrutiny by the elected House of Commons, and a short period as a minister should not lead to a title and seat in the legislature for life."
Instead a limited number of ministers who are members of neither House but accountable to both could be preferable, the report suggests.