When Neill MacColl talks about the privileges he enjoyed growing up with Ewan MacColl and Peggy Seeger for parents, he doesn't mean the trappings of material wealth.

The wealth that flowed in the MacColl household was essentially cultural, such as having the front room full of songs and singers every Tuesday when MacColl's Critics Group met or being taught Freight Train, the first tune Neill learned to play on the guitar, by his mother, who had learned the song from its source, Elizabeth Cotten.

Cotten, who was only appreciated as a great folk-blues musician once she was in her sixties, had actually worked for the Seegers (she was given a job after finding and returning to her parents a young, lost Peggy Seeger in the department store where she worked in Washington) and she went on to show Neill how to play Freight Train her way when, as an 18-year-old, he went over to the US to stay with her for a time.

"That was a really privileged position to be in," says Neill. "It's a bit like learning, I don't know, Goodnight Irene direct from Lead Belly, that kind of thing. Because Elizabeth was a huge figure to me even then and she'd go on to be more widely recognised. But I didn't think of my parents as special - they were great parents but they were just my mum and dad. When you're a kid you think that everybody else's family is like yours."

The first time he remembers realising that his mum and dad might be different from his friends' parents was when MacColl and Seeger came along to his infants school to play a concert, an event that was "wonderful and yet, at the same time, horrifying". The occasion later that might have alerted him to his dad's real status as a songwriter, when Roberta Flack took The First Time Ever I Saw Your Face, which MacColl had written for Seeger in the late 1950s, into the top ten singles chart in 1972, apparently made little impact on the family.

"I think it was a bit of a mystery to dad," says Neill. "He and my mum never wrote songs to be hits or even for people to cover, other than - and this made much more of an impression on dad - other folk singers. It was much more significant for dad when one of his songs was taken up and passed into the folk tradition."

There were quite a few of these, as selecting songs both for the Celtic Connections celebration of Ewan MacColl's centenary - Blood & Roses: The Songs Of Ewan MacColl - and a four-CD boxed set that Topic Records will release later this year has confirmed, if indeed it needed confirming.

MacColl, who died in 1989, was nothing if not prolific and Neill's abiding memory of his father is of how hard he and Seeger worked.

"A lot of people seem to think that folk music is just there," he says. "But it's a discipline just like any other style of music and, if you're going to be a good folk musician, you have to put in the hours. It's not an easy route."

While his mother plays umpteen instruments indecently well - she studied classical piano at Radcliffe College in Massachusetts and can still turn in a concert-quality performance - Neill's father was more of a wordsmith, and the imagination and mastery of language that created songs such as Shoals Of Herring, Freeborn Man Of The Travelling People and Dirty Old Town extended to family entertainment.

Contrary to the rather severe, not-suffering-fools-gladly persona with which MacColl is often credited, Neill and his brother Calum found him splendidly funny.

"Dad was a great storyteller," says Neill. "He and mum were out on the road a lot when Calum and I were young, and our grandmother looked after us for a while, but when he was at home he'd spend an awful lot of time during the day making up these stories for us. They'd be really involved and full of characters that he'd made up himself, and when he told them to us at night, they'd be half-an-hour-long performances. He loved words and he transmitted that love to us, really encouraged us to get interested in literature."

MacColl didn't particularly encourage the family to follow him into folk music or to get involved in any kind of music, although both Neill and Calum - the former with Marc Almond, The Bible and David Gray - and their late half-sister, Kirsty, went on to ensure that the MacColl name maintains a presence in the business. (Four of MacColl's grandchildren will also appear in Blood & Roses, including Jamie from chart-topping band Bombay Bicycle Club.) Aside from touring with his parents as a 16-year-old, Neill initially took little interest in pursuing folk music, reasoning that it would be hard for the son of Ewan MacColl to make an impression in that world.

"We used to sit in the front room and listen when the Critics Group met on a Tuesday," says Neill, "and I remember those nights as being full of these weird and wonderful characters. We'd absorb what was going on, with dad and other people appraising how the songs were being sung, but I'm not sure how much of what happened then I carried into later life. By the time I started writing songs I was involved in a different style of music altogether so I wouldn't have asked for, or expected really, advice from my father."

English folksong's elder statesman, Martin Carthy, who will take part in Blood & Roses, didn't participate in the Critics Group, although he was already carving out his reputation when the group was founded in the 1960s, but he came to appreciate MacColl as a "charming, persuasive, hugely knowledgeable, hugely charismatic genius" - even if he didn't share MacColl's opinion of Bob Dylan as "the William McGonagall of his age".

MacColl, says Carthy, was on a personal crusade and was driven to transform the way folk music was presented - he didn't want melodrama. He wanted realism and the Critics Group was generally seen as his centre of excellence.

A song such as the Moving On Song, which MacColl wrote for The Travelling People edition of his radio ballads series and which depicts travellers being evicted unceremoniously, is one of many that bear out Carthy's point about realism. The late Sheila Stewart, of the tradition-bearing family of travellers from Blairgowrie, wouldn't have sung it - and with such passion - otherwise.

For Neill MacColl, though, his father was as much a romantic as a realist.

"Even when dad was being very political, his writing was about his view of what could be a better world and what route to take to get to that place," he says. "And in putting the programme together for Blood & Roses, I wanted to balance that romantic side with more heavyweight songs. The radio ballads have to be strongly represented but in a way, although there's so many so choose from, it's easy to pick 20 of his songs because there are quite a few that we just couldn't leave out. There are also some - his anti-Thatcher stuff for example - that haven't stood the test of time quite so well as others. There won't be too many surprises but there should be room for one or two. It's really about showing what a good songwriter dad was."

Meanwhile, as a celebration of one parent's legacy is about to come to fruition in 2015, the other parent has a significant birthday to celebrate too, as Peggy Seeger turns 80 in June. With a well-received album, Everything Changes, released towards the end of last year and her concerts showing her to be as bright as ever, Seeger will celebrate her 80th birthday where she has lived much of her life: on the road.

"Mum's amazing," says MacColl. "She still does so many things ridiculously well. She's kept out of Blood & Roses because we needed the song choice to be objective and we felt she might colour it too much if she gave her opinion on what should be included. But I said to her, 'You have your own big birthday coming up, what do you want (meaning for a present)?' And she said, 'I want you and Calum to go out on tour with me.' She's our mum, so how could we refuse?"

Blood & Roses: The Songs Of Ewan MacColl is at Glasgow Royal Concert Hall on Sunday, January 25 as part of Celtic Connections