How they found the man who knew infinity

Last week I met Dev Patel's parents for the first time at a reception at the Royal Society hosted by its president, Professor Sir Venkatraman Ramakrishnan, following a screening of The Man Who Knew Infinity.

"Does he still do the washing up for you?" I asked his mother Anita.

This is an old joke which goes back to 2008, when Dev was 18 years old and had just made Slumdog Millionaire . He was discovering the glamorous world of film premieres and red carpets but Dev told me that whenever he returned to the family home in Harrow, north London, "my mum makes sure I don't get too big headed by making me do the washing up".

Now, every time I meet Dev, he knows I am going to ask him: "Do you still do the washing up for your mum?"

Dev's dad, Raj, who was born in Nairobi, is an accountant, so I wondered whether he had ever told his son to stop wasting time on acting, shackting and instead get a "proper job".

Raj grinned: "I told him your grandfather was an accountant, your father is an accountant, therefore..."

Listening to our conversation, two of Dev's teachers from Longfield in Harrow cut in. Paramjit Virdee, now the school's headmistress, had supervised him in a play when he was 10, and Anne Devine at 11. He won a prize for his performance as Sir Andrew Aguecheek in Twelfth Night .

The odd thing is that in 2008, when Danny Boyle wanted a Jamal Malik, a boy from a Mumbai slum, for the lead role in Slumdog Millionaire , he couldn't find the right youth in all of India but had to come all the way back to London.

And two years ago when the American director and writer, Matthew Brown, wanted the right actor for the role of the Indian mathematical genius Srinavasa Ramanujan, he did not have to look beyond Dev.

"To succeed in bringing Ramanujan to life, I needed someone who the audience could relate to and feel empathy for," says Brown. "I knew from my very first meeting with Dev that his natural charisma, empathy and unbelievable instincts would jump off the screen."

Dev absorbed Robert Kanigel's 1992 biography of Ramanujan, The Man Who Knew Infinity , on which the film is based.

"Playing Ramanujan was very instinctual for me," explains Dev. "I read certain passages from the book, and though there is no footage of him, there are a couple of pictures we had for reference. He was physically very different from me - he was rather portly. Ramanujan was very religious and thought mathematics was like painting without colours; he believed every equation was an expression of God."

Number theory

Hands up if you think you are the world's best mathematician.

Since I detect a forest of hands going up in Calcutta, especially around Belgachia Metro, I ought to tell you about "The Spirit of Ramanujan Maths Talent Search".

The competition has been launched by the producers of The Man Who Knew Infinity in partnership with the American Mathematical Society (AMS) and Carnegie Mellon University mathematician Po-Shen Loh.

"Our purpose is to reach out across the world and try to find the next Ramanujan," according to Ken Ono, Asa Griggs Candler Professor of Mathematics at Emory University, Atlanta.

Ono is the consultant and associate producer on the movie and made sure that all the mathematics we see in notebooks, bits of paper and on the blackboard is "100 per cent accurate".

I catch up with Ono at a party in the drawing room of the Master's Lodge at Trinity College, Cambridge, after he and Prof. Manjul Bhargava, of Princeton, had delivered a lecture on Ramanujan.

One, who has had a life-long interest in Ramanujan, tells me: "We have an app that was assembled by Po-Shen Loh of Carnegie Mellon University which is a collection of 85 clever maths problems and we are inviting people of all ages from all countries to take this quiz and solve problems and accumulate points."

Po-Shen is the founder of www.expii.com, which provides access to the competition that closes on May 20. Last time I looked there were 1,106 participants, with one "Zubin Mukerjee" among the "top solvers".

"We are going to keep track of the best students," pledges Ono. "The idea is that at the end we will have found some very talented students. And the winner will be invited to participate in a follow-up competition run by the American Mathematical Society and, if everything goes well, we will be offering scholarships, education opportunities and development to someone who needs it."

Family izzat

The BBC is promoting a feature film, Murdered by My Father , which shows a father strangle his daughter by stuffing a plastic bag into her mouth in slow motion. Her legs thrash around for several minutes, then she lies still.

Mission accomplished.

The father, Shahzad (played by Adeel Akhtar), feels family izzat has been besmirched because his daughter, Salma (played by Kiran Sonia Sawar), prefers Muslim Boy 1 when he had promised her to Muslim Boy 2, his business partner's son.

Cinema is imitating real life. A girl was suffocated with a plastic bag by her father and her mother while her siblings watched approvingly.

"Many Pakistanis in England live in a time warp," a Lahore resident tells me.

Padma passion

British newspapers cannot get enough of Padma Lakshmi. First we had Padma, who has got it into her head that she is America's answer to Nigella Lawson, offering readers her recipe for "chilli cheese toast" in The Dish, The Sunday Times Food Magazine.

Meanwhile, the Daily Mail reported: "Padma Lakshmi is red hot as she shows off her svelte figure in clinging midi dress..."

Reader reaction to "Tainted ex-spouse of Salman Rushdie" was not entirely friendly.

"The woman would attend the opening of an envelope if she thought it would get her publicity," was among the comments.

But one lusty male did concede: "I likes em fiesty! And brown!"

Taxing times

In Britain, tax evasion is illegal, but not tax avoidance, though it can be morally in a grey area. Amitabh and Aishwarya Rai Bachchan might spare a thought for David Cameron, whose late father, had shares in an offshore trust.

Ian Cameron's name came up in the leak of 11 million documents held by Panama-based law firm Mossack Fonseca.

The PM is in the clear but a little of the mud is bound to stick. The affair might well encourage a Private Eye cover.

Tittle tattle

Since Narendra Modi is giving lunch to the Duke and Duchess of Cambridge, here's some useful intelligence.

Top model Neelam Gill, who attended a reception given by the couple last week, said afterwards that Kate told her "that she loved Indian food, so I told her that she'd be fine with the spices. But William told me that he struggles with the spices so I told him to watch out."

I suggest cheese on toast for William but minus the chilli.

Security is apparently going to be a big problem - protecting Indians who get in the way of the British snappers.