The battered green Transit van parked in leafy St John’s Wood, looked out of place among the sleek sports cars and Bentleys. Passers-by on that icy February morning 50 years ago might have suspected it belonged to burglars, attracted by the rich pickings in one of London’s most exclusive neighbourhoods. But as the engine spluttered into life, a group of hippy types, accompanied by children and dogs, piled into the back.

Among them was Paul McCartney, the most famous musician on the planet, who was leaving his palatial home to hit the road in 1972 for the first time since 1966 on a “secret tour” with his new band Wings.

Macca, who later admitted it was a completely “off the wall” idea, seemed to be taking a deliberate step into the wilderness. Wings would tour Britain in the Transit and a rented Avis truck and just turn up unannounced in the hope of getting a gig.

But among the members of the band there was a sizable gap in musical experience.

Guitarist Denny Laine had spent part of the 1960s as a founder member of respected rock band The Moody Blues ‑ whose hits included chart-topper Go Now and would go on to record the classic Nights In White Satin with Laine’s replacement Justin Hayward.

Linda McCartney, by contrast, had spent the preceding decade working as a photographer, but was considered, by her husband at least, to be an integral part of the line-up despite having almost no keyboard skills.

Their first gig was at Nottingham University for no better reason than the band needed a break from driving.

Parking outside the student union office, roadies Ian Horn and Trevor Jones were sent in to announce that there was an ex-Beatle outside looking for a gig.

One of the first people to see Wings was student Jim Jacobs, who had travelled up from Cirencester to visit his girlfriend there. 

He recalls: “A buzz went round the campus that something was going on up in the Portland building. Someone got a fistful of tickets and we wandered up there.”

This journey back into the world of a working musician was something McCartney had long fantasised about. Having failed to persuade The Beatles in their latter years that they needed to “get back” to their roots as a club band and play some small shows, it was only now with his band Wings he was able to realise his dream.

He could finally return to a live stage in front of a paying audience, something he hadn’t done in almost six years since the Beatles last American tour. 

“I just want to get into a van and do an unadvertised Saturday night hop at Slough town hall or somewhere,” McCartney told the Melody Maker in November 1971.

Yet a few months later, when he turned up in Nottingham to play his first-ever gig with Wings, the nascent band was already in the midst of a critical battering and faltering sales. 

Their debut album, Wildlife, released two months before the impromptu tour of British university towns, had stalled at an extremely un-Fab number 11 in the UK charts.

Its rushed and raw collection of scrappy, seemingly half-finished songs (the record was recorded in barely a week) was a very long way from the smooth, orchestral sounds of The Beatles’ Abbey Road.

Its low chart placing suggested that Macca fans were increasingly in agreement with critics among the music press. Rolling Stone magazine even wondered in print if Wildlife was “deliberately second rate”.

Back in Nottingham, the band checked into a bed and breakfast (baby Stella sleeping in a cot made from an old drawer) before turning up to play their debut gig the following afternoon.

“There weren’t many there to be honest,” recalls Jacobs. “Only about 150 or 200 people. We walked in simply not knowing who was going to be there.

“We had no idea who it was until the moment they walked out on stage.”

And amazed as they were to see Macca standing there, the performance was not exactly what they expected.

“They kept stopping and starting in the middle of various songs and Paul was asking the crowd, ‘What do you think of that one so far?'” says Jim. 

In fact, the band had only mastered a small handful of tracks from the maligned Wildlife album to perform live, so the show was fleshed out with classic rock and roll covers, including Long Tall Sally and Lucille.

“In between the various songs they went into little conferences to decide what they were going to play next,” adds Jim. “They had no running order.

“It was a very claustrophobic gig. The noise was really bouncing off the walls ‑ it was a very high stage with a very low ceiling… I think they played for a couple of hours. We were stood there in silence.”

The slightly baffled crowd at least can say they got value for money. Tickets for the debut Wings concert cost 40p (around £6 today).

Not bad to see a former Beatle. But the low ticket price had a direct effect on the band’s finances, as drummer Denny Seiwell recalled in a later interview. “Paul would go, ‘Here we go, one for you, one for you, one for you…’ It was probably the most money I ever made touring with Paul and it was nothing, you know.”

Although Linda got through the first Nottingham gig without any blunders, the cracks in her musical abilities would soon begin to emerge.

Two nights later, whilst on stage in York, when Paul introduced the band’s new song Wildlife to the audience, no sound emerged. Looking over to his wife, Paul saw her mouthing that she had forgotten the chords.

By then, the idea of the “secret tour” was blown. The band decided to abandon it after two weeks when news of their impromptu appearances led to student unions around the UK setting up their stages in advance, just in case McCartney and Co chose to stop by.

The other Beatles kept silent, seemingly ignoring Paul’s back to basics tour.

The music press either sneered or seemed baffled at the “Mom and Pop”-style circus that the tour became. Backstage, there were no rock and roll excesses. 

Rather, witnesses observed Heather and Mary McCartney, then about nine and three, drawing pictures together whilst baby Stella slept in a cot.

But Macca and Linda ‑ who died of breast cancer in 1998 ‑ seemed to be having a ball.

“Those [gigs] were mad,” he said in a later interview. “We just made it up: 50p on the door, no hotels booked, no gigs booked, no nothing booked. Even the lowliest group through history has had a hotel booked for them, but we were just mad.”

In a later article, he recalled: “It’s a completely off-the-wall idea for someone who’d been in The Beatles to go and completely start from scratch and, you know, looking back at it I was like, ‘Why did we do it?’ But it was a great memory.

“We had some laughs – you can imagine some of the hotels we managed to scrape into! We would literally get there about 7pm at night, and there wasn’t the greatest selection left!

“But it was really fun and a great bonding experience for the band.”

More, better organised tours followed, including one of Europe in an open-top bus. And the next year, Macca’s 1973 Wings album Band On The Run would bring critical and commercial acclaim back to his door. 

Which was an outcome most of the students in Nottingham University on that cold afternoon in 1972 would not have put money on.