At last the map was finished. Called Wild World, it had taken Anton Thomas three years to draw and included pictures of 1,642 animals. There was something else special about it too: it contained no human-drawn borders. 

Thomas says that it represents an "idealistic planet." A growing number of people seem to share his idealism.

Many of the elections being held around the world this year have immigration high on the agenda. Britain's prime minister Rishi Sunak has repeated his determination to stop the small boats carrying illegal migrants across the Channel, and to deport unwelcome newcomers to Rwanda.

Labour's Keir Starmer has promised to make border policing more efficient. Reform's Nigel Farage says he wants to reduce net migrationThe difference between the number of people moving into a country (immigrants) and the number of people leaving the country (emigrants). to zero.

In the US, the number of people entering the country from Mexico is a headache for Joe Biden which Donald Trump is determined to exploit. The words quoted on the Statue of LibertyA joint French-American project, finished in 1886, the statue celebrates the abolition of slavery and international friendship. Its original name was Liberty Enlightening the World. - "Give me your tired, your poor, your huddled masses yearning to breathe free" - ring hollow.

There are those, however, who believe that restricting immigration is both immoral and economically damaging. Some insist that national borders should be abolished altogether.

The economist Alex Tabarrok argues in The Atlantic that freedom of movement is a basic human right. Most people living in a rich country are there by an accident of birth: that does not make them more entitled to enjoy its benefits than those born elsewhere. Borders simply reinforce injustice.

He adds that immigrants bring new skills and stimulate an economy. According to the Centre for Global Development, abolishing borders would double world GDPShort for Gross Domestic Product, the measure of all the goods and services produced inside a country..¹

Michael Sandel raises some difficult questions in his podcast The Global Philosopher. Politicians like to distinguish between asylum seekers and economic migrants - but is there a moral difference between those dying from bombs and those dying from poverty?

Border controls are sometimes justified on the grounds that countries work best when there is a shared sense of identity based on history, culture and religion. But, Sandel asks, is that really the case?

Moreover, since most people believe that it is wrong to stop someone leaving a country, "why is it not equally wrong to prevent that same person from arriving?".²

Is it a good idea?

Yes: It is incredibly unfair that some people have miserable lives just because they were born in a poor country rather than a rich one. Migrants bring drive and enterprise and should be welcomed.  

No: There would be chaos. According to Gallup, 15% of adults - over 750 million - would move to another country if they could. Of those, 158 million would head for the US and 34 million to the UK.  

Or... Migration affects not only the places people move to but the places they leave. It is hugely damaging to a country if it trains doctors and nurses only to see them move abroad for better pay.