Philip Rycroft, the former head of the Brexit department has said that a reorganising of the Scottish and UK governments is required to protect the future of the United Kingdom, according to the BBC on Monday.
Speaking to BBC Scotland, Rycroft urged the government to "think quite radically" about the relationship between the nations of the UK if the union is to endure.
One suggestion he made was for a "super-charge" to the existing constitutional arrangements, with "Whitehall upping its game on devolution."
But Rycroft added that "given the pressure Brexit will put on the system, that might not be enough", saying a move to a more federal structure for the UK might be needed.
"There is fresh pressure on a relationship that was stressed anyway, and we've not even reached the end of the beginning yet. There's a whole lot more stuff to come down the Brexit track which will require intense discourse, dialogue and discussion between the governments of the UK. I find it difficult to say at the moment how the existing structures can withstand that sort of pressure," said Rycroft.
He continued: "Any incoming UK government is going to have to think hard and fast about what the offer is to people in Scotland and Wales and Northern Ireland in terms of engagement in the next stages of the Brexit process, critically to demonstrate that the interests of the people of Scotland, Wales and Northern Ireland will be incorporated in that process and respected. Otherwise there is a risk that in leaving one union, this other union flounders."
"The UK as a policy is under pressure as never before. Scotland came quite close to deciding to leave the UK, and Brexit has further destabilised that situation. There is clearly a risk that majority opinion in Scotland over time moves to support independence," he added.
Rycroft went on to claim that the political situation in the UK is now in "unprecedented territory" and he noted that he had "not experienced anything remotely like this in 30 years in public service."
Since the results of the 2016 European Union referendum were announced, independence has been a hot topic in Scotland with Scotland's first minister and Scottish National Party (SNP) leader Nicola Sturgeon immediately calling for a second independence referendum which it hopes to hold in 2020.
Sturgeon claims there is a "clear democratic mandate" for a second referendum given Scotland's decision to remain in the EU, but she wants assurances that the vote will be "beyond legal challenge."
Sturgeon has accused Prime Minister Boris Johnson of plotting an "anti-democratic move" in shutting down parliament to push through a "catastrophic" no-deal Brexit.
Johnson, however, claims that "the separatists in Scotland drone on and on about breaking up and smashing the oldest and most successful political union" to detract from their "appalling domestic record."
Scottish independence would only "return Scotland to the European Union after Brexit, complete with the euro, the full panoply of EU laws and the surrendering of Scottish fish just when they have been taken back by this country."
Meanwhile, Labour Shadow Chancellor John McDonnell, who remains in talks with the SNP to oppose a no deal Brexit, said that a future Labour government would not block a Scottish independence referendum.
Rycroft's statements come against the backdrop of pro-independence rallies in Scotland and Wales.
Marches for Scottish and Welsh independence were held over the weekend with thousands in attendance, and demonstrators indicating growing dissatisfaction with the Brexit deadlock.
Northern Ireland's place within the UK has also come under question, after it voted overwhelmingly to remain in the EU.
The British border in Ireland remains a predicament which plagues the governing Conservative Party, which says it does not want to see the erection of a hard border in Ireland but also rejects staying within the EU Customs Union, which would prevent the two Ireland's breaching their common regulatory alignment, a key aspect of the 1999 Good Friday Agreement.
