During his decade as prime minister, Tony Blair resisted the blandishments of portraitists who sought to capture him live on canvas. But last November, five months after leaving office, he agreed to sit for the British painter, Jonathan Yeo.

The picture, commissioned by the Honourable Society of Lincoln’s Inn, reveals a calm, silver-haired Blair, positioned slightly off-centre, with no apparent setting or background. His pale suit melds into the surrounding space, so the prime minister’s face appears to loom in an almost ghostly fashion, and the viewer is drawn immediately into his unflinching pale stare.

Gone are the boyish confidence and the broad smile of the early Blair. But gone, too, is the harrowed, exhausted figure he cut at the end of his term in office.

Mr Yeo, son of the former Conservative minister Tim Yeo, has painted him in contemplative mode – stripped bare of any pretence or swagger. He appears to have set out to paint Blair the man, rather than the politician. However, the remembrance poppy pinned to his jacket – the only flash of colour in this almost monochrome work – is a clear reminder of war and, more directly, his war.

“I wanted to find some subtle way of referring to war,” says Mr Yeo, who has painted many international figures, including Rupert Murdoch. “The poppy served several purposes: not only is it a painterly splash of colour, it also suggests blood on the collar.”

It is also a reference to the red rose logo Labour adopted in the 1980s, often found in the corner of election literature, although it has since been abandoned.

Mr Yeo knew that he was painting one of the most controversial figures in recent history, and that his portrait would elicit extreme reactions. “I was doing my best to be objective and not judgmental and to leave the portrait as ambiguous as possible. People will project their opinions on to it. No one feels neutral about Blair.”

It was not the first time that Mr Yeo had encountered the former premier professionally. He gained rare access to him in 2001 to paint him as the centre panel of his House of Commons-commissioned election triptych.

But, in contrast to the extended time in the studio that he was granted for the new portrait, he had to grab brief moments in settings such as Mr Blair’s private jet, and had no formal sitting with him.

This earlier representation shows the then prime minister in bullish health, and a 2003 oil by Mr Yeo of Mr Blair – not painted from life – shows him laughing confidently.

The artist reports that contrary to the calm aura of his portrayal of Mr Blair, his subject was charismatic, chatty and in good health during the sitting at his Chelsea studio. The resulting oil portrait will be hung in the great hall of Lincoln’s Inn, alongside 16 other official portraits of British prime ministers, in March.