What's the secret of a great comedy song?

All great comedy has a rhythm.

From Eddie Izzard's surreal flights of fancy to a tightly-paced episode of Friends, there's a tempo and a structure that lets you know when the punchline is coming, and when the audience will laugh.

Many writers compare creating a joke to writing a melody: When the words land in the right place, it just feels right.

So if comedy is like music, why are funny songs so hard to get right?

It's partly because the rhyme scheme can reveal the punchline too early, puncturing its effectiveness. And also because the structure of pop music relies on repetition. Nobody wants to hear the same joke three times in two minutes.

These are sort of revelations that comedian Phil Nichol has been making as he records his new podcast, Songs In The Key of Laugh.

"I've not really studied comedy songs before, I've just been a fan of them - but I've started to realise they have to be unpredictable to work," he says.

"You have to break that verse-chorus structure, because you don't want the audience to know where the song is going."

Nichol got his own start as a musical comedian, as part of the Canadian trio Corky and the Juice Pigs.

In the late 1990s, they became a cult act with songs like Dolphin Boy, French Cowboys and Todd! (a 13-second track consisting of the word "Todd" screamed at increasing levels of intensity), with a slot on Mad TV and endorsements from Dudley Moore and Steven Spielberg.

Now a successful stand-up and West End star in his own right, Nichol realised during lockdown that the increasingly over-saturated podcast market still hadn't got a show that explored the world of comedy songs.

He put the idea to his neighbour, session musician David Timms, during one of those long, drawn-out walks - and by the time they got home, a plan had been hatched. Not least because Timms had cunningly manipulated Nichol into working with him.

"It was a cold, rainy muddy day, and David fell over and it made me laugh so much that by the end of it I thought, 'I'd better do something with this guy.'"

The first episode launched last week, with the duo dissecting their own music, while interviewing comedy songwriters like Tim Minchin, The Mighty Boosh, Barenaked Ladies and Jess Robinson.

So what are Nichol's favourite comedy songs of all time? Er, he doesn't know. "That's impossible," he cries. But here are six that have tickled his fancy this week.

Warning: Some of the following songs contain lyrics that people may find offensive.

1) Bo Burnham: Welcome To The Internet

Taken from Bo Burnham's bleak but hilarious lockdown comedy show Inside, Welcome To The Internet portrays the toxic addictiveness of the internet - and its promise of "a little bit of everything all of the time".

"Bo Burnham writes really beautiful songs, and this particular song sums up a way a lot of us are feeling about the internet.

"It's really political and it's really charged with the question of what is the internet doing to us? And are we becoming numb to to these to these images? Is it healthy? But I think he does it in the most playful and wonderful way.

"Inside was just ridiculously good. I watched it two nights in a row and it was one of those times where I thought, 'I may as well give up because that's absolute genius'."

2) Monty Python: Sit On My Face

Joyfully smutty, the Pythons' ode to oral sex appeared on their 1980 Contractual Obligation Album, and opened their 1982 film Monty Python At The Hollywood Bowl. Sung to the tune of Gracie Fields' Sing As We Go, it also got a US radio station fined $9,000 (£6,620) for profanity in 1992.

"I was raised in a deeply born again Christian family, in something called the Brethren Assembly. At one point, they believed buttons were evil - because buttons come undone easier, and it leads to sex standing up.

"So we weren't allowed to listen to secular music, or watch secular films or TV shows when I was growing up. But my brother Andrew, who is about six years older than me, used to have a souped-up Ford Capri with a tape deck. We'd sit in this car and listen to secular music: Stevie Wonder, Ray Charles and then he discovered Monty Python.

"I was about 10 or 11, and it was the naughtiest thing in the world. I don't even think I knew what sit on my face really meant - but I loved the absolute silliness of it. To this day I cannot listen to that song without laughing."

3) Billy Connolly: The Welly Boot Song

Written by poet George McEwan while working in a lemonade factory, The Welly Boot Song became Billy Connolly's theme song in the early 1970s. Although it was a fun singalong, the comedian stressed the lyrics had a serious point, saying "A great sign of poverty in Glasgow is wellies in the summer."

"Although we weren't allowed to listen to secular music, Billy Connolly slipped through because my parents are Glaswegians.

"The Welly Boot Song was something we used to sing on the drive home amongst the hymns and other things. It's got a lovely innocence to it but actually, it's quite politically-charged as well.

"When you take apart the lyrics, he's talking about poverty in the working classes and farmers in Scotland."

4) Flight Of The Conchords: Business Time

Parodying the tumescent anthems music of Prince and Barry White, Business Time looks at the practical realities of seduction on bin night...

"I really wanted to pick a more obscure Flight of the Conchords song - but when I went back and listened to Business Time, I was sold. It just has so many great gags.

"It's such a great juxtaposition of that sexy slow funk music with the completely nerdy lyrics of an average guy in a bedroom situation. I think that's why it's so relatable.

"Even though they're making fun of a particular type of man, we've all felt we're not quite up to scratch, in the bedroom department."

5) Corky and the Juice Pigs: Eskimo

A breakout song by Nichol's former comedy troupe, Eskimo has often been misattributed to Jack Black's band, Tenacious D. He sets the story straight...

"I hope you don't mind me choosing one of my own songs - but I do think it is one of the really great comedy songs, and it works because it has a really tragic underbelly.

"We wrote it in a hotel room in Australia, where they were showing a documentary about these Inuits who had gone off seal hunting. Our manager at the time was gay and I remember Greg [Neale, co-writer] saying, "Imagine being the only gay Inuit on the seal hunt."

"Our bandmate Séan came in and started singing, 'I'm the only gay eskimo'. And then we played the song all day, coming up with more and more rhyming couplets. And then we started doing impressions of how other people would sing it - Van Morrison and The Proclaimers. It just made us laugh so much.

"The song became really popular when we did it on Mad TV - but this is back in the early days of the internet and a record company released it [without our permission] and said it was Tenacious D, because they didn't know who we were.

"Tenacious D still get asked to play it now - so it's gone really far without our band ever being really, really popular, and I think that's why I like it."

6) Ivor Cutler: Good Morning! How Are You? Shut Up!

A brilliant flight of lyrical fancy, Ivor Cutler's Good Morning is full of eminently quotable lines like: "Elephants - Oh, I love that big talk!"

"Ivor Cutler. Should have been the poet laureate. Scottish National Treasure.

"This song is produced by George Martin, who produced The Beatles, and it's got the most beautiful, twisted lyric. It says something deep, but in the most surreal, childlike way.

"It's probably my favourite all-time comedy song. It may even be one of my all time favourite songs. I can't not enjoy it."

Phil Nichol's podcast Songs In The Key Of Laugh is available now.