An Australian ferry forced to dock for six months in Edinburgh because it is too big to fit in a Tasmanian port has finally left Scotland.

Spirit of Tasmania IV, built in Finland, arrived at the Port of Leith in December due to issues with existing infrastructure in the city of Devonport.

Delays, cost overruns and other mistakes have caused a huge political row in Australia, leading to Tasmania’s infrastructure minister and operator TT-Line’s chairman resigning in August last year.

The vessel departed the city for Hobart on Monday, where it will undergo a final “fit-out” before its future crew undergo training, the company said.

But a technical issue with the liquid natural gas (LNG) fuel system in May meant its departure was further delayed.

It underwent sea trials in the North Sea in June.

TT-Line chief executive Chris Carbone said: “We expect the vessel will be alongside in Hobart in late-August for the final fit out of items including Tasmanian-made mattresses and table tops, cabin stores and artwork, and to undertake vessel crew training.

“The training for our crew involves emergency response exercises, passenger muster simulation, firefighting drills, deployment of lifeboats and the mass evacuation systems.”

The saga, which has a number of parallels with Scotland’s own difficulties procuring new ferries, has been dubbed a “fiasco” and “stuff up” by opposition politicians.

Spirit of Tasmania IV is one of two vessels set to replace two 30-year-old ferries on the Bass Strait between Tasmania and the Australian mainland state of Victoria.

But the LNG ships are years late and the cost of building them has soared by A$94m (£47.5m) from A$850m (£430m) when the contract was signed in 2021.

It also emerged that the ships are too big to fit the harbour facilities in Devonport and the required upgrades will not be ready until 2026 or 2027.

The cost of the harbour redevelopment, meanwhile, has more than quadrupled from an original estimate of A$90m (£45.5m).

The ship was initially moved to Leith from a shipyard in Finland last year due to concerns it would be damaged by pack ice over the winter months.

TT-Line was paying A$47,534 (£24,031) per week to berth the ship at Forth Ports, according to figures published by the Tasmanian government.

Both the ferry company TT-Line and ports firm TasPorts are state-owned, and in August 2024 the infrastructure minister, Michael Ferguson, and TT-line chairman, Mike Grainger, both resigned.

Dean Winter, leader of the opposition Labor party, described it as the “biggest infrastructure stuff up” in the state’s history.

It was initially reported the ship could spend up to three years in Leith before attempts were made to lease it to a European operator, but that did not work out.

Mr Carbone, from TT-Line said the work to develop the new terminal at Devonport was now well under way.

The vessel will travel to Hobart via Gibraltar, the Cape Verde Islands, Cape Town in South Africa and Port Louis in Mauritius.

It will dock in Fremantle in Western Australia for about four days while customs paperwork is processed before making the final trip to Hobart in late-August.

A spokesperson for Forth Ports said: “The Spirit of Tasmania departed Leith on Monday en-route for Australia.

“We wish her well on her journey.”