BBC:

Down in the polls and desperate to hold on to his position, Malcolm Turnbull knows a leadership challenge could be near.

After all, it's only three years since he launched his own "spill" to oust former prime minister Tony Abbott.

Once a leader looks vulnerable, the political rumour-mill goes into overdrive and trusted Cabinet colleagues can start to look like rivals.

Choosing to back down on the emissions legislation shows that Mr Turnbull wants to avoid testing his support in a parliamentary vote.

Even if the current threat retreats, his authority has been damaged and his opponents have gained momentum.

Mr Turnbull said he would not proceed with the emissions target – part of his National Energy Guarantee (NEG) – because it had no prospect of passing through the House of Representatives, where he has only a slim majority.

He said the NEG would still require electricity retailers to cap their prices and provide more "reliable" streams of power.

"Cheaper power has always been our number one priority when it comes to energy policy," Mr Turnbull said.