Music students dazzled by the Louise and Peter Mensch show at the Albert Hall

“Why are you still bothering?,” Louise Mensch asks her husband, Peter, the New York rock band manager who guides the careers of Metallica and Jimmy Page. “You made a lot of money a long time ago and it’s your 60th birthday today?”

It’s a question which might normally be posed within the family home. But today the former Conservative MP is quizzing her husband on a stage at the Royal Albert Hall in front of 50 spellbound students.

The audience are young musicians, chosen to attend a masterclass in music management as part of the London venue’s new education programme.

Whilst Mr Mensch reveals how he made AC/DC international megastars and saved Madonna’s career, the session also provided a revealing insight into the relationship which prompted his wife’s surprise resignation from Parliament last August to move to New York with her husband.

“I don’t have to introduce Louise, you know her,” Mr Mensch told the students as the former politician, who agreed to be “chairman” for the session, sat alongside her husband.

Unused to a supporting role, and betraying a slight East Coast twang, Louise soon began to impose herself on proceedings.

“I want to get through you guys’ questions,” she told the audience. “But first I have some questions of my own. Let’s talk about Metallica. You stole them from their manager didn’t you? ” “Louise knows my career better than I do,” Peter admitted.

Later an exasperated Peter complained “You keep cutting me off” when Louise tried to move the conversation on. “I’ve got so many questions,” she told him.

“It’s my show and I can do what I want” insisted Peter, who was “shushed” by his wife when he threatened to divulge an indiscreet story about Samantha Cameron.

Louise first met Peter when she invited him to speak at the Oxford Union in 1990.

Years before they became an item, Mr Mensch helped Louise gain work experience in the music business. “I spent all of one Summer interning at MTV Headbangers Ball and record companies,” she told the students. “I worked for nothing.” Now she is helping him choose his next starlet.

Unveiling a video by new signing US singer Kassia Conway, Mr Mensch revealed: “Louise said ‘I don’t know who that is but that song is a hit’. Louise has ‘interesting’ tastes, so if she says it’s a hit…”

“What made you say ‘no’ to the middle class life and your parental expectations of becoming a lawyer and take your 400 records to college and run the college radio station?,” asked Louise, keen to explore Peter’s formative years. “Free records and free concert tickets,” he joked.

“I want to give the musicians a chance to ask some questions,” said Mr Mensch perhaps hoping for an easier ride.

How much percentage does the manager of Foals, Red Hot Chili Peppers and The Black Keys, take from his artists? “It starts with 15 per cent and ends in 20 per cent,” he said. “I take the commission off gross not net. Three members of Metallica have private jets. They can do that with their own money, not with mine. I’m not going to pay for their private planes.”

Even the biggest stars need to listen to their manager, said Mr Mensch, who once looked after Courtney Love and Smashing Pumpkins. “The manager tells the artist ‘You’re songs are a piece of shit, go write new songs.’ Ava Dore (1998 Smashing Pumpkins single) was lousy. We told them ‘you can make better music’. Billy Corgan fired us. It turned out we were right.”

Bands are “passive-aggressive” and “seethe with anxiety over songwriting royalties and sharing the spotlight”, the students were told.

Closing the session, Louise expressed her true feelings for her husband. “I just want to say, I love you dearly and I’m so proud of you. Happy birthday.” Mr Mensch paid gallant tribute to his “beautiful wife”.

And why does he keep going after 32 years in management? “I have a chip on my shoulder the size of K2. I want to eat everyone else’s lunch. My acts are the best, goddamit.”

If Metallica ever lay down their axes, the Louise and Peter Mensch show could prove a sell-out attraction for years to come.

Foals and Emeli Sandé have also held workshops with music students as part of the Royal Albert Hall educational sessions, staged in the venue’s Elgar Room. Violinist Nicola Benedetti will hold a masterclass in the Autumn.

What Peter Mensch did for… Madonna

“I took a brand name and doubled her sales. She was in a slump but (1998 album Ray Of Light) became her second biggest hit of all time.

It was because I picked the right single, Frozen. She wanted the title track. She was wrong. A year later, in her begrudging way, she said ‘You were probably right’.Yes, Madge, I was.”

What Peter Mensch did for… Foals

“When the first played Reading, Yannis (Philippakis, singer) faced sideways. I said ‘If I’m going to manage you, you are going to have to face the audience.’ Now they are a great live band. When Warner Bros wouldn’t pay over £90,000 to finish their second album, we paid the rest. Playing an extra matinee show at the Royal Albert Hall, that was my idea. I’m putting up £75,000 to film the whole day for a DVD.”

What Peter Mensch did for… Snow Patrol

“Gary Lightbody’s demo for the song Just Say Yes was a slow and dirgey in a Chasing Cars way. We knew it was a hit but we said it needs a tempo, it has to be more ‘up’. The finished version moves along quicker and the chorus is an octave up. That’s what managers do. Sometimes the musician needs guidance.”