Less than five months after appointing his first cabinet, Prime Minister Malcolm Turnbull today unveiled a major reshuffle to address ministerial casualties, departures and the elevation of Barnaby Joyce to the leadership of the Nationals.

After yesterday’s dumping of Human Services Minister Stuart Robert, the final question to be addressed before a reshuffle was the future of Special Minister of State Mal Brough, who stood aside over the Christmas-New Year break pending a police investigation of his role in the Peter Slipper affair. Brough this afternoon announced he was stepping down altogether, on the basis that the AFP had advised him their investigation would be continuing for some months. His decision allows Turnbull to proceed with a full reshuffle, described by the Prime Minister as a “dynamic team”.

Deputy Prime Minister Barnaby Joyce will retain his current portfolio of Agriculture and Water Resources, while Gippsland Nationals MP and rising Nationals star Darren Chester is promoted into cabinet, taking Warren Truss’s portfolio of Infrastructure and Transport. He’ll be joined by new Nationals deputy leader Fiona Nash, who’ll be Minister for Regional Development, Regional Communications and Rural Health; the cabinet is to be expanded one position to 22 members to accommodate the Nationals.

Trade Minister Andrew Robb, who announced he would be leaving politics at the next election during the week, will be replaced by Queensland MP Steve Ciobo. Mathias Cormann becomes permanent Special Minister of State, a role in which he has been acting in addition to his day job as Minister for Finance, where he will be assisted by Peter Hendy.

Other promotions include current parliamentary secretary Senator Scott Ryan (Vocational Education and Skills), assistant ministers Alan Tudge (Minister for Human Services) and James McGrath (Assistant Minister for Immigration), Victorian MP Dan Tehan (Minister for Defence Materiel and Veterans’ Services), and under-threat NSW MP Angus Taylor (Assistant Minister to the Prime Minister for Cities and Digital Transformation). Tehan’s promotion means that the key chairmanship of the Joint Committee on Intelligence and Security will become available.

National Senator Matt Canavan becomes Minister for Northern Australia, while Senator Concetta Fierravanti-Wells is promoted to become International Development Minister. Like Taylor, Fierravanti-Wells is under threat in NSW and in danger of losing her preselection; their promotion at least in part is a signal from Turnbull that he doesn’t want any further ructions in relation to their positions.

A full ministry list is here.