It has been revealed that seven of the 11 boats serving Shetland are over 30 years old.

The news follows The Herald’s exclusive investigation into Orkney’s ageing ferry fleet which raised a range of concerns over the boats connecting Scotland’s islands with the mainland.

An exclusive investigation by the Herald showed that inter-islands ferry fleet serving Orkney is so old that the island community has been forced to consider contingency plans for several emergencies, ranging from evacuation to RAF support. 

The archipelago’s MP, Liam McArthur, said woes of CalMac’s much younger boats in the Western Isles had “masked” problems in his constituency where, in desperation, island councillors have mooted rejoining Norway in a bid to grab the attention of the government on the mainland.

Shetland’s council, like Orkney’s, has also been lobbying hard for cash to buy new ones and has had some success, securing funding from the UK Government for a replacement for the 37-year-old Good Shepherd, the boat which serves Fair Isle.

Read more: 'We might need RAF airdrops': The 'forgotten' ferry crisis gripping Orkney

Shetland council leader Emma McDonald, back when that announcement was made, said the British money “had saved Fair Isle as an inhabited island”.

Ms McDonald had also personally praised former Deputy First Minister John Swinney for revenue support provided for day-to-day run-in costs of the inter-islands services. Orkney also gets cash to keep its ferries going - but not buy new ones.

Islands watchers have noted the very different tones in the way Orkney and Shetland approach similar problems.

Orcadians tend to argue that Shetlanders get more money than they do: and this is backed up by figures. Shetland, of course, is further away from mainland Scotland.

Shetland last month started quietly distributing a professionally produced “cheat sheet” of its biggest asks of Edinburgh and London. The document, which has been handed out to politicians and stakeholders but not published, repeatedly refers  to “partnerships" with both Britain and Scotland.

The Herald: Looking over to the small island of Dore Holm with the sea weathered natural arch visible, off the west coast of mainland, south east of Stenness, Shetland. Picture credit Paul Tomkins, VisitScotland.

Shetland is not just after ferries: it wants tunnels too. It reckons it can dig under the relatively short channels that separate its mainland to three of its nine inhabited outer islands: Bressay, Whalsay and Yell. And it would like another such crossing from Yell to Unst, Scotland’s most northerly island.

The language in the document is all about pooling and sharing resources, not about confrontation.

“Shetland Islands Council understands that any project to replace ageing ferries with new vessels, or with tunnels, cannot be expected to be solely  the responsibility of central government,” reads the section on new short tunnels.

“Just as our islands’ incredible energy resources should be a shared benefit between Shetland, Scotland and the  UK, the transportation between those islands should  be a shared cost.

Read more: Warning that CalMac’s woes have 'masked' a ferry crisis in Orkney

“This is the fairness which lies at the centre of our partnership; Shetland, Scotland and the UK sharing costs, and sharing benefits. The benefits to all of us  from replacing ageing ferries are widespread and  clear. There are economic benefits to be derived from making transit between Shetland’s Mainland and our outer islands faster, easier and more resilient. There are social benefits, too, from making our outer islands feel closer and more accessible. And, of course, there are meaningful environmental benefits to replacing old, carbon heavy ferries with a combination of greener vessels and tunnels.”

The council is also lobbying for a special island tariff for power - it is, after all, 3C colder in Shetland than the UK average - and support for broadband roll-out.

Shetland is calling for fairness - and praising UK and British politicians. Orkney is complaining about in its inequitable treatment and lambasting leaders in London and Edinburgh. So much so that it is threatening to quit Scotland and Britain, or at least its council is.

Orkney councillors earlier this month grabbed international headlines by backing a motion to look at its constitutional future, even considering crown dependancy status or rejoining Norway.

Insiders are clear that this gambit was designed to provoke help with ferries and other funding issues.

Shetland has made such noises before. Islands watchers are curious to see which approach works best. Scottish Government sources stress they make decisions on funding and policies based on needs, not PR stunts or lobbying campaigns. But will they be distracted by dramatic calls for autonomy more than they are wooed by careful diplomacy?