LONDON (Reuters) - Just days after Prime Minister Theresa May formally served the European Union with divorce papers, a powerful affliction appeared to strike some in Britain: Brexit fever.

FILE PHOTO - EU and Union flags fly above Parliament Square during a Unite for Europe march, in central London, Britain March 25, 2017. REUTERS/Peter Nicholls/File Photo

Amid a row with Spain and the EU over the status of Gibraltar, a former leader of May’s Conservative party, Michael Howard, even said she would be prepared to go to war to defend the small British territory near Spain’s southern tip.

Beside headlines about war over “the Rock” in Britain’s Euroskeptic press, there was also enthusiasm for an as yet unconfirmed plan to ditch European burgundy passports and return to the sturdy blue British passports of the past.

Readers of the Daily Telegraph were told that while the once mighty Royal Navy was weaker than it used to be, it could still “cripple” Spain if required.

A columnist in The Sun suggested May should threaten to expel all 125,000 Spaniards from Britain and tax Rioja wine unless Madrid backed off over Gibraltar, ceded to Britain under the Treaty of Utrecht in 1713 but which Spain wants back.

So is Brexit fever sweeping Britain?

“Some people are getting a bit overexcited and I would take everything that was said over the weekend with a massive pinch of salt,” Anand Menon, professor of European politics and foreign affairs at King’s College in London, told Reuters.

The prime minister, an initial opponent of Brexit who won the top job in the political turmoil that followed the referendum, now has two years to sort out the terms of the divorce before it comes into effect in March 2019.

May, 60, has one of the toughest tasks of any recent British prime minister: holding Britain together in the face of renewed Scottish independence demands, while conducting talks with 27 other EU states on finance, trade, security and other issues.

May’s spokesman sought to calm matters down, saying that what Howard “was trying to establish was the resolve that we will have to protect the rights of Gibraltar and its sovereignty”.

Asked if that would include ultimately sending a naval task force to protect Gibraltar as Britain did to the Falklands 35 years ago, he said: “That isn’t going to happen.”

“RED, WHITE AND BLUE BREXIT”

The Daily Mail carried a factbox on “Who’s got the biggest armada?” while praising putting the blue passport back into “a red, white and BLUE Brexit”.

But the belligerent mood, shared by only a section of British society, could also have a more serious impact on the course of Brexit, according to Menon.

“If the talks break down over money or trade or whatever and the mood music is perfidious Europe, then it makes it a lot easier for the prime minister to deflect blame and hold a snap red, white and blue election,” said Menon.

“It also arguably makes it harder for May to compromise over Brexit,” he said.

The outcome of the negotiations will shape the future of Britain’s economy, the world’s fifth biggest, and determine whether London can keep remain one of the top two global financial centers.

For the EU, already reeling from successive crises over debt and refugees, the loss of Britain is the biggest blow yet to 60 years of efforts to forge European unity after two world wars.

In Britain, though, the mood was jubilant - and at times bordering on the surreal.

Another piece in the Telegraph called for the return of Britain’s “imperial” units - confusing ancient weights and measures which sit alongside the metric system: Beer is served in pints but petrol in liters.

Kelvin MacKenzie, a columnist who edited the Sun newspaper from 1981 to 1994, had strong words for Spain.

“We are only just into these Brexit negotiations and to be honest I have already gone from jaw-jaw to war-war,” he wrote. “Our friends in Europe are quickly turning out to be our foes. It’s only in recent history where Germany and Italy have been on our side.”