Scotland's path to independence could become far rockier and more complicated than Alex Salmond might like, if the equally independent-spirited northern isles of Shetland and Orkney get their way.

That, at least, is the view of their respective Lib Dem MSPs Tavish Scott and Liam McArthur. In a paper submitted to the UK government's consultation on the independence referendum, the pair have provocatively suggested that the two island groups' willingness to stay within an independent Scotland cannot be taken as given.

Nor, if it comes to that, does ownership of "their" oil, which, by one measure, includes a quarter of the oil and gas wealth being claimed as Scottish by Salmond's nationalist government.

Presumably that would include the massive, largely untapped reserves which lie west of Shetland; what, too, of the immense marine energy resources off Orkney, so central to Salmond's vision of Scotland becoming a green energy powerhouse?

Scott and McArthur have reinvigorated a long-standing notion that the former Viking earldoms of Shetland and Orkney have their own, quite distinct views on self-determination and identity.

In fact, many islanders don't really regard themselves as Scots at all and are at times openly hostile to Edinburgh rule, which they regard as remote and uncaring about their particular needs, interests and culture.

Instead, the pair suggest, if the Scottish National party were to win independence in the autumn 2014 referendum the northern isles could refuse to leave the UK, or demand a much greater local take of Scottish oil revenues or even declare independence themselves.

So Scott and McArthur are exhorting their constituents to grasp the opportunity to seize back influence as part of that process, from taking greater local control over the seabed, to scrapping redundant oil and gas rigs, to getting a fatter slice of future oil and marine energy incomes.

Scott, the former Scottish Lib Dem leader, who saw his party crushed at last year's Scottish elections as voters punished it for Nick Clegg's alliance with the Tories, believes this question is political "dynamite".

Leaving aside the niggling issue with the Lib Dems insisting the pro-UK parties will win the referendum anyway, Scott believes the islanders – who until the 15th century were ruled from Norway - have their own rights to self-determination.

Interviewed by BBC Scotland's Sunday Politics Show, Scott said it was far from certain his constituents would support Scottish independence: "Who knows?" he said, before venturing the suggestion that the Northern isles would expect to benefit materially if Scotland seceded.

If it's a geographical share of oil and gas you're after, I think Orkney and Shetland have a pretty big stake in that debate too. I think we have some pretty good [bargaining] chips to play and those are the ones the people of the islands should decide how they want to play in these coming years.

There is precedent here: when Sullom Voe on Shetland became one of the UK's largest oil transfer ports in the 1970s, the islanders brokered a very lucrative levy on every barrel of oil landed there. Over 30 years, Shetland has amassed an oil fund worth some £300m.

That deal was influenced by Jo Grimond, the then Orkney and Shetland MP and former Liberal leader. Scott and McArthur's paper on independence recalls that Grimond's view was that:

The last thing the Northern Isles want is to be ruled by Glasgow trade unionists and Edinburgh lawyers.

It goes on:

The Northern Isles therefore will want to use the current debate about Scotland's future to fully assess their needs and aspirations and ensure that these are properly reflected in whatever constitutional arrangements are settled upon. Orkney and Shetland are likely to have different requirements and potentially different destinations on this constitutional journey but they share a strong sense of local identity.

Scott and McArthur's paper – which is at best provocative and, in constitutional terms, at least playful - has a political purpose. It plays to the Lib Dems localism agenda and the party's wider frustrations with what it sees as the increasing centralisation of power under Salmond by his government in Edinburgh.

Yet despite the implication that the SNP's nationalism is disliked, there is evidence the SNP is actually increasingly popular in the northern isles, after traditionally not standing candidates there. Last May, the SNP ran the Lib Dems closer than they would like, with a Shetlander getting elected to Holyrood for the SNP on the Highlands and Islands list vote. It is also standing candidates in May's council elections, to try and build up pro-nationalist momentum.

Scott dismisses the SNP's chances, pointing out that both he and McArthur are now the only Lib Dems at Holyrood elected by constituency; the other three Lib Dem MSPs came in on regional lists. Traditionally, he added, only independents stand for Orkney's and Shetland's local councils while the islanders hate being dictated to by mainlanders, whether from Edinburgh or London.

Insisting his paper was apolitical, and designed to stir the islanders up, Scott said on Monday:

I'm not in any way prejudging the views of our constituents. It's for us islanders to decide what we want, and how best use the current bun fight between Westminster and Holyrood to further our islands' needs. If we don't we will be run over by the steamroller of either the UK government or Edinburgh government. When devolution happened in 1999, I thought it would see more powers devolved within Scotland, but has it hell. We've seen enormous centralisation of power in Edinburgh.

There is already debate about Scott's motives; the Shetland Times, which runs Scott's column, has one too by its editor Paul Riddell, where he states:

The Scottish Liberal Democrats' disastrous showing in the Holyrood election last year, and Mr Scott's decision to stand down as leader, have placed him in a marginal position in Scottish politics. That has given him time to start thinking about how Shetland ought to position itself prior to rather than after the referendum. It also allows him to make mischief as only opposition politicians can do.

But Riddell pays off his column, broadly supportive of Scott's agenda, with this gibe: