David Cameron will be hugging Mr Modi pretty tight as well during his three-day visit. Mr Cameron has made efforts to forge better relations with India, visiting the country three times since 2010. Comparisons will be made with the enormous fuss made of China’s president, Xi Jinping, during his visit to Britain last month, but the Indian diaspora shouldn’t have much to worry about. Despite the fact that Mr Modi’s is not a state visit, unlike that of Mr Xi, he will still be getting the full works: a Buckingham Palace banquet, an address to Parliament and even a chance to chillax with Mr Cameron in the prime minister’s country house, Chequers.

Both sides hope to get more of the same out of Mr Modi’s visit. With a slowing economy India, in particular, is looking for more investment in infrastructure. But as Richard Heald of the UK India Business Council explains, India is also looking for more “digital economy” businesses to come in, such as satellite and data-transmission companies. Mr Modi, like Mr Xi before him, also wants closer links with the City of London. A formal dialogue to deepen financial ties between the governments of India and Britain was started just over a year ago, and Mr Modi’s trip is expected to feature announcements on the issuing of more rupee-denominated “masala bonds” in London.

Yet for all the investment flying between the two countries, the relationship remains undercooked. Germany and France, in particular, have invested heavily in their relationships with India, pledging billions of dollars in aid for, respectively, green energy and smart-cities initiatives, dwarfing anything Britain gives these days. Trade in goods between Britain and India is also relatively small.

It is also evident that Mr Modi has been in no particular hurry to get to Britain, having visited dozens of other countries before getting around to the former colonial master. When he gets there, he will probably hear from Mr Cameron about the rising intolerance towards Muslims that Mr Modi’s Bharatiya Janata Party (BJP), with Hindu-chauvinist roots, has turned a blind eye to and even encouraged of late. If Mr Cameron does not raise this issue publicly, he will face criticism that he is brushing human-rights concerns aside, as he was accused of doing during Mr Xi’s visit.

And there is also the perpetual irritant of the British visa system. Since 2010 the number of Indian students enrolled at British universities has halved, mainly owing to a tightening of visa requirements (see chart). As a result, an increasing number of Indian students are deciding to study in Australia and America. British universities complain about this as much as Indian students, for they lose out on the lucrative tuition fees that overseas students pay.

Yet the theatre of Mr Modi’s visit is designed for domestic consumption as much as anything else. The support of the Indian diaspora has been crucial to Mr Modi’s success in India. The Rashtriya Swayamsevak Sangh (RSS), a Hindu-nationalist outfit that has strong influence within Mr Modi’s BJP has helped to organise the big rally at Wembley. That event will be projected back to India as a massive show of support—handy for a man who just lost a vital state election in Bihar (see article).

Mr Cameron has plenty to gain as well. At the general election in May, according to one report, for the first time the Tories polled 1m votes from among ethnic minorities, the overwhelming majority of whom were Asians. Among Hindus and Sikhs, the Tories even outpolled Labour. Putting in a Wembley appearance alongside the popular Mr Modi probably won’t do the prime minister’s own political ratings any harm either.