The British passport is worth the same as Argentina's under a 'Hard Brexit'

The British passport would be worth the same as Argentina's if the rights of free movement are stripped from the UK in a hard Brexit, according to a study of passport power.

The study, by citizenship planning firm Henley and Partners, takes into account how many countries can be visited without applying for a visa.

Currently Germany tops the league with 177 countries open out of a maximum of 218. The UK is joint-third with France, Italy and Spain at 175 countries.

Argentina is down in 22nd place, below Romania, San Marino and Chile.

"We did studies of what makes one nationality more valuable than another, and of course the British nationality is one of the best in the world," Professor Dimitry Kochenov at the University of Groningen, who compiled the report, said at a conference in London.

"And then just as a joke we looked at the effect of Brexit - hard Brexit without any free movement with full detachment from the rights that come from the European Union - and it ended up with the UK passport at the level of the Argentine document," Kochenov said.

Here is the chart:

He added: "That's why this war against common sense waged by the government of this country is extremely dangerous. The stakes are extremely high."

The British passport faces an overhaul once the Brexit negotiations, due to start next year, are completed.

While the words "European Union" will disappear from the front of the passports, the government has indicated that their colour could also change from burgundy to blue, The Times reported in September.

"We are considering potential changes to the UK passport after the UK has left the European Union," the immigration minister, Robert Goodwill, said in reply to a parliamentary question about reintroducing Britain's "old blue style passport" from the Conservative MP Julian Knight.

Kochenov said that London would be hardest hit in a hard Brexit scenario, where the government prioritises immigration control over keeping some aspects of single market membership. In that case, a separate "London citizenship" may make sense.

"A London visa, while it might sound absurd, might actually be a good idea given the drastic gap between what the government thinks is good and what really is good for London," Kochenov said.

"A city can actually exist disconnected from the physical area surrounding it as long as its connected to a strong economy somewhere else," he added.