A parliamentary private secretary (PPS) is an MP appointed by a minister to be his or her unpaid assistant.
Normally a PPS is a junior backbench member of the governing party.
An appointment as a PPS is seen as the first rung on the ladder towards ministerial office.
A PPS acts as a minister's eyes and ears in Parliament, making sure the minister is kept well informed of backbench opinion on his or her performance.
PPSs are expected to vote with the government and to keep a low profile in the House.
A PPS cannot, for example, be a member of a select committee or table an amendment to a government bill.
The prime minister currently has two PPSs.