ON the one hand you have Ian Anderson; mad staring eyes, wild hair, hands gesticulating and occasionally playing a breathy flute on one leg, sometimes dressed in a ragged overcoat and sometimes sporting a cod-piece, and of course, the man behind one of the most successful and long-lasting rock bands - Jethro Tull. On the other hand you have Ian Anderson; country squire and former owner of Scottish fish farms that were so successful that he was awarded the Scottish Businessman of the Year Award in 1997, and is a conservationist and charity worker. Also, he has just received an MBE for Services to Music.

Yes, it's hard to believe, but these two men are one and the same.

"The enduring thing though, is that I'm a musician. I'm not involved in fish farming at all now. I've profited by seeing another side of life. Musicians tend to live in a rarified world and it's good to be able to do other things," he says.

Although Scottish by birth, Ian Anderson formed Jethro Tull from the ashes of a Blackpool-based band and moved to London and gained a residency at the prestigious Marquee Club. This band, erroneously labelled Jethro Toe' on its' first single, is celebrating it's 40th Anniversary this year with a 29 date tour of the UK. Ian is taking this opportunity to thank Tull fans for their continued support over the past four decades. "The loyalty of our fans keeps us in work and pocket money. Some artists have fickle fans but the more loyal and committed fans ensure that the work of bands like Led Zeppelin, Jimi Hendrix, The Stones and us won't fade away," he said.

Apart from their bluesy first albums like This Was, Stand Up (a UK chart topper), and Benefit, the band has notched up over two dozen hit albums including Aqualung, Heavy Horses and Under Wraps. Two albums hit the top of the charts in America, a Grammy Award was earned in 1989, and their UK singles tally is in double figures with hits such as Living in the Past and The Witch's Promise.

With all this, I asked Ian to describe the music of Jethro Tull - was it folk rock, prog rock or something else? "It's all and none of those. Someone once said that Tull is Bach meets the Blues'. Our music has the discipline and formal musicality exemplified by Bach, yet there is something gutsy in it. It's probably somewhere between heartfelt and headfelt. Actually, Bach was a brilliant improviser. I reckon if he were a musician today, he would probably be a jazz musician. Beethoven would be in a heavy rock band."

It has been reported that Ian hates the name Jethro Tull' (the band was named after the 18th century English agricultural pioneer who invented the seed drill). "I've never been mad keen on the name. It was on a list of names our agent gave us. We got the residency at The Marquee with that name and it stuck. I've always been a bit uncomfortable with it as the Jethro name can conjure up images of The Beverly Hillbillies'." But there were other names to pick from? "Yes, but one of them was Candy Coloured Rain."

Jethro Tull are a unique band. There aren't many that sport a flute as a lead instrument, and another thing that has always set the band apart is that, despite the fact that when the band was forming and touring in the 70s, he has never used drugs. "Not yet," he pointed out, "but there's plenty of time. Mind you, when the time does come, it'll be legally administered and I'll look forward to the pain-relieving properties."

Obviously, Ian has to sing songs every night that he's been singing for 40 years, and I wondered whether he is big on nostalgia, is he - to quote his own song - Living In The Past? "I am not one for nostalgia and prefer to live in the present and future. However, some of our audience like the nostalgia bit and it's a bit like a trip down memory lane for them. For us, it's not about playing a song which could be over 30 years old. It's about playing something that's 24 hours old, since that's when we last played it on stage."

To celebrate the 40th Anniversary this tour will focus on the early years of the band. "For years," Ian explained, "We've done a best of' set list, but for a change about 80 per cent of the show will come from the first three or four albums, but of course we'll play a song or two from other eras - those songs that reflect stylistically the big picture."

For this special tour Ian is joined on guitar by Martin Barre, who joined the band at the end of 1968. On drums is Doane Perry, who has been in the band since 1984, and completing the line-up are David Goodier on bass and John O'Hara on keyboards. Also, as an extra bonus on this special tour - most performances on the tour will feature a special guest, some of whom may well be past members of the band.

Billed as An Evening With Jethro Tull', the 40th Anniversary tour takes in The Lowry at the Salford Quays on Wednesday April 9 (tickets are £25.50 and £28.50 and are available from the box office on 0870 787 5790), and The King George's Hall in Blackburn on Thursday May 15 (tickets are £23.50 and £26.50 and are available from the box office on 01254 582582).