Two cantankerous legends hold court in the Devon sunshine

One festival, three days, four major cancellations… and two obstreperous veterans doing their thang on Bank Holiday Sunday night.

Bishopstock, four miles outside Exeter, is no longer touted as a "blues" festival – merely a "music" one – but the majority of the wrinkled faithful who've descended on 850-year-old Bishop's Court have come to see blues… not least the doddery quartet that dubs itself the Delta Blues Cartel. The fact that the latter entity, which includes Homesick James, Honeyboy Edwards, and Robert Johnson protégé Robert Lockwood, has bailed out at the last minute on account o' Foot'n'Mouth (!!) has got more than a few folks severely riled, and not even the equally last-minute addition of blues fan Van Morrison to tonight's bill is appeasing them.

When you really dig in when you really dig in when you really dig in... it lifts you up it lifts you up it lifts you up...

Off mic he yells "motherfuckin' bitch" – not a phrase one recalls from Tommy Edwards' version – then grins again at the band in their matching midnight-blue suits. The guy is on fire.

Winding up with the tried-and-tested Sonny Boy Williamson medley of 'Help Me' and 'Good Morning, Little Schoolgirl', Van is simply mind-blowingly great – as great as he was on 1973's It's Too Late to Stop Now, as great as he's ever been singing White Soul from the gut of rhythm and blues, as great as a grumpy old git like him could possibly be.

Good morning, little schoolgirl,
Can an old man go home with you?
Tell your mama and your papa,
I was once a schoolboy too!!

WAS NINA SIMONE EVER A SCHOOLGIRL?

As [Nina Simone] wades around the stage with a horsehair fly-whisk, drinking up the adoration of the Bishopstock crowd, it's hard to picture little Eunice Waymon on the streets of Tryon, North Carolina. She seems to have been born with the hauteur of an empress – or at least a "High Priestess of Soul", as she prefers to be billed.

Simone, of course, could never be reduced to a mere "soul" artist. From her earliest days at the Juilliard School, she's always defied categorisation, eluding pigeonholes like "jazz", "blues", "soul", "folk" and "gospel", yet melding 'em all at times into a unique Aframerican style. Me, I love her singing Gershwin and Berlin most of all.

Sadly, we don't get much "soul" – and little of anything else worth a damn – from Simone at Bishopstock. Sunday's headliner manages to play a grand total of about seven songs, interspersed with a great superfluity of "I LOVE YOU"s and "AWLRIGHT"s, not to mention an apparently unscheduled absence of leave lasting almost 15 minutes. By the end of her set I've remembered exactly what a batty, pampered old diva she is.

I don't know why I expected anything different. For a few moments during an opening 'Amazing Grace', that cavern-deep contralto – with its almost aristocratic diction – threatens to move me, but it isn't long before I'm feeling severely pissed off with not only her but all the silly sistas who keep wailing "NINA! WE LOVE YOU!" every time La Simone's voice cracks or she hits the wrong chord on her Steinway. Moreover, the high irony of Simone reeling off the names of "my black ancestors" (Marcus Garvey, Langston Hughes, Paul Robeson et al) before an almost entirely Caucasian crowd appears to sail over most people's heads.

She sings 'Black Is The Colour (Of My True Love's Hair)' and the Pentecostal 'Every Time I Feel the Spirit' in a drag-queen bark whose range is utterly shot, then plods over to the centre-stage mic to render – and even grind her heavy hips to – a hopeless version of 'Here Comes The Sun'. The stab at Dylan's 'Just Like A Woman' is equally abysmal.

"Where the hell am I?" Nina asks after her long disappearing act. "Is Devon in London?" No, you old bat, it's on Mars. For the umpteenth time, she brandishes the fly-whisk like it's some African sceptre; for the umpteenth time the crowd yelps its radical-chic appreciation, then dutifully sings along to the dated/overrated 'Mississippi Goddam'. "You better keep loving me and buying my albums," she commands after telling us how tired she is.

There's a minor consolation prize tucked at the tail end of the set: a version of 'I Want A Little Sugar In My Bowl' that reminds you of just how great Simone was and could still be if she got over her grande-dame airs. Sung with care and sensuality, its multiple entendres left to speak for themselves, 'Bowl' is Nina at her dark, bluesy, egregious best.

The final insult? Not even being able to get to my old charabanc on account o' Nina demanding the road be kept clear for her wretched Mercedes to pass.

Back to France with you, you old coot!