At family-owned food shop Popat Mithai & Farsan, owner Vijaya Popat and her all-female team are often so busy dealing with customers in multiple languages that there\'s barely time to sit down, let alone chat with a nosy journalist.

Mrs Popat set up the business in Leicester back in 2011 to sell Indian sweets and savouries, and it has grown from two members of staff to 15 today. And an online operation was launched in 2018.

Serving the South Asian diaspora in the East Midlands city and further afield, sales soared during the coronavirus pandemic, as customers sought more comfort food - the tastes that they or their forebears brought to the UK from countries including India, Pakistan, Bangladesh and Sri Lanka.

Mrs Popat\'s son Shyam was put forward to speak to the BBC. \"My mum is widely known in the community as being the person that runs the business,\" he says.

\"And they all want to speak to her specifically to see if she can source particular things.\"

He adds that it\'s not just first generation immigrants, or those who have just moved to the UK recently, that make up the core customer base. Instead it is also the second generation, who might be buying food for their families, and increasingly online.

\"During the lockdowns the website was a total lifesaver, and now we\'re out of lockdown it has become a thriving arm of the business in itself,\" says Shyam Popat. \"Online sales now account for approximately one-quarter to one-third of the entire turnover of the business.\"

In addition to importing products from South Asia, the shop also buys from Kenya.

The boost that the world\'s diasporas give to trade between countries is difficult to quantify, but governments are increasingly aware of the economic importance of migrant populations and their descendants.

Kenya announced in September that it would be creating a new ministry for Kenyans living abroad, and US President Joe Biden has announced that he will tell next month\'s US-Africa Leaders Summit in Washington that he wishes to \"amplify diaspora ties\".

But just how big are the world\'s diasporas? There are currently 281 million people who live in a country other than the one in which they were born, according to the 2022 World Migration Report from the United Nation\'s International Organization for Migration (IOM).

That number equates to 3.6% of the global population, or one in 30 people. And it doesn\'t include any children those people have that are born in their new country, nor does it include the descendants of former migrants.

For this reason, the IOM defines the terms \"migrants\" and \"diasporas\" (which comes from the Greek to scatter) separately. The later also including descendants of former migrants \"whose identity and sense of belonging, either real or symbolic, have been shaped by their migration experience and background\".

This equates to billions of people, but an exact number is very difficult to quantify given that it is determined by a person\'s cultural identity. Even the IOM said back in 2020 that \"currently there are no attempts to measure global diaspora populations per se\".

More from the BBC\'s series taking an international perspective on trade.

What is certain, is that the entrepreneurial drive within migrant populations has long been recognised. A 2010 report by Organisation for Economic Co-operation and Development said that immigrant entrepreneurs were better educated than their native counterparts, and more likely to create a new business.

And often those firms are involved in the importation of food, clothing or other goods from a migrant\'s former country, such as Indian-born Vijaya Popat and her thriving shop in Leicester. The store, and others like it, played their part in India\'s exports to the UK totalling $10.4bn last year.

Based in Paris, Olivier Habiyambere is helping to boost Kenyan exports to Europe. He is the founder of website Kenyan Diaspora Market, which imports food and clothing in bulk from the African country, and then sells it to customer across the European continent.

Mr Habiyambere, who was raised in Kenya, came up with the idea for the business when he moved to Paris to study and met others from Kenya and East Africa.

\"Everybody wanted Kenyan products, but the issue was bringing the products from Kenya to here,\" he says. \"People could pick up the products when they went to Kenya, but it\'s not like they could do that every year.\"

So he launched the business in April 2022 to offer Kenyans in Europe an easier way of buying products from home. Mr Habiyambere adds that business has grown steadily, helped by Kenyan communities spreading the word via WhatsApp groups.

While Kenyan Diaspora Market is focused on Kenyan migrants, Glasgow-based website Agora Greek Delicacies now has more non-Greek customers than those from within the UK\'s Greek communities.

It was set up a decade ago by husband and wife Christina Lyropoulou and Michael Sofianos, who had gone to university in the UK. They now employ 14 people and supply imported Greek food and drink to restaurants, cafes, individuals, and other businesses.

\"We started expanding to the British audience - so those travelling to Greece or had Greek friends,\" says Ms Lyropoulou. \"And our online shop saw an increase in sales of about 1000% in the first months of the lockdown.\"

Prof Pragya Agarwal, a behavioural and data scientist at the University of Loughborough, regularly buys products originating from her native India for herself and her family in the UK.