JOHN Keane, winner of the 2015 Aesthetica Art Prize in York, has two new shows running in London, should you wish to see more of his work now that the exhibition at York St Mary's has concluded.

Keane's winning entry, four paintings from his Fear series from 2013, were on show in the Castlegate church building until last Sunday. Working in oil paint and linen, Keane drew on images from the Stalinist terror of the 1930s, sourced from mug shots of arrested victims, some well known, some anonymous, as they faced the Moscow show trials. Monumental in scale, these paintings distilled the essence of the human emotion usually to be found at the root of all violence: fear.

Keane rose to prominence in 1991 when he was appointed as the official British war artist during the Gulf War, and he has continued to investigate political questions, while also producing portraits of notable individuals such as the late Mo Mowlam and Kofi Annan.

New work by Keane on the themes of power and conflict are on show in his Speaking To Truth show at Flowers Gallery's gallery at 20 Cork Street, Mayfair, London, until June 27. "The subject matter ranges for ISIS atrocities to Vladimir Putin to journalist Rebekah Brooks and Rupert Murdoch," says John.

His second show, The Wisdom Of Hindsight at 82 Kingsland Road, Shoreditch, London E2, is a retrospective to mark 30 years since Keane's first solo show at Flowers Gallery. This survey of paintings from throughout the former official British War Artist's career will run until June 27 too.

The two shows coincide with the launch of Mark Lawson's book, Troubles My Sight: The Art Of John Keane, in which Lawson draws on extended conversations with Keane in both his early and late career to chart how the artist has turned painting – an art form now regarded as conservative – to radical political purposes. Named after a quote from W B Yeats's poem The Second Coming, this 240-page book contains more than 200 colour illustrations and introductory texts by musician Brian Eno and professor of international relations Alex Danchev.

Reflecting on his Aesthetica prize in York, Keane says: "It felt very exciting; a bit unbelievable; very gratifying in the extreme. It was a long time since I'd put in for a competition but I liked the way this one was set up. So often contemporary art awards are skewed towards a particular medium but this award gave equal status to different working practices, so that endeared it to me, as so often painting has been reduced in importance, like in the Turner Prize, where it's often not given due consideration."

The Fear paintings on display in York were "fragments of an extreme and terrible moment of modern history", says Keane. "But as I am constantly reminded, the dangers of such events happening again must be guarded against, and it is my hope that art can help to play some small part in this.”

Keane's combination of photography and paint is reminiscent of the working methods of Andy Warhol. "Warhol is an obvious antecedent; someone whose work I've always rated since I was an art student," he says. "Playing with the surface is all part of the process, as much as the subject matter is important...but obviously Warhol was dealing in glamour; I'm dealing in misery."

The Aesthetica Art Prize, run by York's international art and culture magazine Aesthetica, will return to York St Mary's next spring for its fourth year.