Britain and Australia held another round of talks to progress a free trade deal, the British envoy said on Thursday, as both countries seek to strike an agreement in mid-June. Britain is pursuing a deal with Australia as one of the pillars of its post-Brexit strategy to build stronger commercial and diplomatic links in the Indo-Pacific region. Both countries in June said they have agreed on the vast majority of issues for a deal, which official estimates say could add 500 million pounds ($708.4 million) to British economic output over the long term. But with some sticking points remaining, British Trade Minister Liz Truss and her Australian counterpart Dan Tehan held talks late on Thursday, the British High Commissioner to Australia Vicki Treadell said. "We are working hard to have an agreement in principle at the bilateral between Prime Ministers Johnson and Morrison on June 15," Treadwell told reporters in Canberra. "Last night secretary state Liz Truss had another session with Trade Minister Tehan and respective chief negotiators." The proposed deal with Australia is the most advanced of several deals being pursued by London. Member nations of the Comprehensive and Progressive Agreement for Trans-Pacific Partnership (CPTPP) on Wednesday agreed to allow Britain to start the process of joining the pact, Japan’s economy minister said. ($1 = 0.7059 pounds)