Kris Kristofferson, Apollo, Hammersmith, London

On the big screen, he has been directed by Sam Peckinpah and made love to Barbra Streisand, but in the field of country music Kris Kristofferson's own legend precedes him. Born in Texas, he won a Rhodes scholarship to Oxford University but quit academia to train as an army helicopter pilot. The military lost its appeal, and he spent the latter half of the Sixties scuffling on the Nashville breadline. Then, while working as a janitor at Columbia records, he landed a helicopter in Johnny Cash's backyard to deliver the demo tape of the man in black's future No1, "Sunday Morning Coming Down".

On his 1970 debut album Kristofferson's songwriting laid claim to many mantles. He was the poet laureate of the one-night stand ("Help Me Make it Through the Night"), rogue philosopher ("Best of All Possible Worlds") and social activist ("The Law is for the Protection of the People"). In the years since, booze and drugs may have taken revenge on his boyish good looks but his songbook has grown to encompass multitudes.

And yet the 67-year-old man with silver hair and beard wrapped up in a trench coat looks exposed and nervous with only a lectern, acoustic guitar and harmonica holder for company. Kristofferson is a both a self-effacing and engaging performer. The songs engage but his voice and musicianship barely reach the foothills of the majestic heights he scales as a writer. With no musical support his aged vocals are more strained than ever, so he gives a comical running commentary on the more glaring shortcomings.

And yet it is possible to forgive him anything as the songs filled with deadpan humour, tender insights, wry wisdom and deep truths tumble forth. What other country artist has an ode to companionship inspired by Fellini? Who else would quote Yeats's "prophetic poem" "The Widening Gyre" before presenting the "pathetic song" it inspired, "Slouching Toward The Millennium"?

That was an effacement too far. Like nearly everything he plays, the song resonates deeply. He gives rare perspectives to both concerns of the heart and his impassioned political beliefs. "Here Comes That Rainbow Again", a masterfully drawn meditation on human compassion, is dedicated to Cash. "The Pilgrim", a song about the public image and private reality inspired by Cash, is dedicated to audience member Bob Geldof.

Kristofferson's universe encompasses celebrity icons, the contemporary Native American warrior John Trudell ("Johnny Lobo") and the Iraqi artist Leila Attar, killed in a bombing raid under the Clinton administration. There's the distant glow of fondly remembered passion in "Loving Her Was Easier" and he spits out the embittered curses of "Sam's Song" like a bar-room fighter.

As a parting shot he wonders what his father would have advised him to do in America where "the dream has been turned around". The answer, he decides, would be "Tell the truth and stand your ground". Needless to say, daddy would be proud.