Less than two years ago, TPG Telecom was firing off letters insisting it didn’t need to share regional phone networks with rival Optus as it tried to cement a $1.8 billion deal with Telstra.

The commercial incentives for TPG and Optus to expand their regional coverage were “more likely to drive the parties apart than to lead them to enter into a network sharing or roaming agreement with one another”, TPG told the competition watchdog in November 2022.