His snow-white hair, the pristine white clothes and the dreamlike figures in the painting behind him, already give this portrait of MF Husain a sense of otherworldliness.

When you discover the regal figure, known as the Indian Picasso, died before Bounds Green painter Yanko Tihov could complete the work, his visage takes on an extra ghostliness.

But sentiment aside, the skill and grace of the work alone, has seen it chosen from 2,377 entries to be one of the 55 works that make up the world famous BP Portrait Award Exhibition.

Yanko was there last week to see it unveiled at the prestigious National Portrait Gallery in London and says: "I'm very sad that he (MF Husain) didn’t see the finished picture but more sad that he didn’t see it at the gallery as at private view lots of the artists had their models there and they were posing for photographs and I think he would have liked that.

"I'm still very close with his agent in New York and he thinks it may be the only portrait he sat for while he was alive. So that makes it even more special."

The 37-year-old who works from a custom-built studio attached to his home near Bounds Green station, first met Mr Husain in London in 2007 and asked him to sit for a portrait purely for his own pleasure.

Born in Bulgaria and inspired by his grandfather, a self-taught artist, Yanko graduated from the National Academy of Arts in Sofia and moved to London in 2001 to pursue his career and has found success as a printmaker, with his current series using images of passports and maps to explore identity.

But his first love is still drawing and he is often commissioned to do portraits, most recently of famous publisher, poet, spoken word performer and philanthropist Felix Dennis, who died last week.

"I always start with a pencil, " says Yanko. "For me drawing is the main thing and I believe you can do anything from a good drawing."

It was this skill which he says captured the attention of Mr Husain, who was one of the most celebrated and internationally recognized Indian artists of the 20th century, working mostly in abstract style.

He was 93 when he first sat for Yanko in 2008, surrounded by his own paintings at his Park Lane studio in London and the pair spent about eight days together over the next three years.

"We didn't really chat, he was painting in between, but we did talk about drawing and he was fascinated by that.

"But it was mostly a quiet experience which I like when I'm working."

He adds: "Painting was always something I wanted to do since I was very little. It's something that chose me and I always knew it was right because when I paint it's the only time I don't feel time passing."

Yanko, who is represented by TAG Fine Arts and Store Street Gallery in London, had put the portrait to one side to concentrated on commissions but when he heard of Mr Husain dying in the summer of 2011, aged 96, he became determined to finish the portrait, which features glimpses of work from Mr Husain's Civilization Series.

He says: "His passing made me look at it again and definitely contributed to me wanting to finish it."

The National Portrait Gallery, St Martin's Place, WC2H, until September 21. Details: npg.org.uk, yankotihov.co.uk