A win for Scotland's pro-independence parties in the United Kingdom's regional elections has increased the pressure for a new referendum on whether the country should go it alone, an option its voters rejected just seven years ago.

Much has happened since 2014, not least the UK's Brexit vote and its subsequent departure from the European Union, which most Scottish voters opposed.

For that reason alone, a second referendum might stand a better chance of producing a leave vote that would end the 300-year union between Scotland and England. The government in London will try to head off a new vote, but it has no ultimate veto to block it forever.

Last week's regional polls also came at a time of renewed political tension in Northern Ireland, similarly linked to the aftermath of Brexit, although the province was not voting this time around.

In Wales, formally incorporated into the united realm in the 16th century, the pro-independence party did relatively poorly. But the poll outcome there was nevertheless at odds with the general trend among its English neighbors, with gains for the opposition Labour Party.

The results of a single set of elections cannot be taken as signaling the eventual breakup of the United Kingdom. But they did reflect the forces that might eventually drive its constituent members apart.

Looked at UK-wide, the election results were positive for Prime Minister Boris Johnson's ruling Conservative Party. But most of its gains were in England, specifically among voters in the previously industrialized Labour strongholds of northern England who had also supported Brexit.

Ironically, for a party officially called the Conservative and Unionist Party, Johnson's Conservatives enjoy a majority in England alone.

If he wants to reinforce the union, his challenge is to convince voters in the other nations that it has not become just the English Party.

A majority of Scottish voters rejected independence in 2014 in part because remaining in the union guaranteed their country's continued membership in the EU, a perceived benefit that has since evaporated.

Northern Ireland voters similarly opposed Brexit in 2016, even if their unionist politicians did not. The imposition of a post-Brexit sea border between mainland Britain and the province has reawakened tensions there.

The pro-British, mainly Protestant majority believes it is being left behind by London, while the predominantly Catholic republican movement argues that the new post-Brexit dispensation reinforces its argument for union with the Republic of Ireland, an EU member.

If Johnson and his successors fail to convince the people of Scotland, Wales and Northern Ireland of the benefits of union, could Great Britain one day be replaced by Little England? And what would that mean for the nation's status and influence on the international stage?

Those who opposed Brexit in 2016 would argue that the UK was already imperiling its position by opting to leave a powerful international trading bloc and choosing the ill-defined option of going it alone.

In the midst of its COVID-19 challenges, the Johnson government was also accused of further abandoning its soft-power status by slashing its generous aid budget, much of it earmarked for countries least able to cope with the impact of the pandemic.

British governments have generally argued that the UK has succeeded in maintaining a post-imperial status that has allowed it to "box above its weight".

That has included its aid partnerships and its extensive diplomatic influence, not least as a balancing force between the United States and Europe. It is a permanent member of the United Nations Security Council and a nuclear power, even if its nuclear-armed submarine fleet is based in Scotland.

Even if the British might have tended to exaggerate the extent of their modern international influence, there is little doubt that it would be diluted if the UK broke up into its constituent parts.

That will not happen anytime soon. Pro-independence Scots will not risk an early second referendum that they might once again lose. Additional investment for Northern Ireland and Wales might convince their citizens that they are better off inside the union.

There is no doubt, however, that the invisible glue that once held the union together has dissolved, not just as a consequence of Brexit but also because of major economic changes and rising inequalities both between and within the regions.

That presents a challenge for mainstream politicians of whatever stripe who argue that, in an uncertain world, the nations of the UK will remain stronger if they stick together than if they were to eventually drift apart.

The author is a senior media consultant for China Daily UK.