If you happen to pass Justin Hayward driving his car in the days before he goes on tour, don't be alarmed if he appears to be screaming his head off – it's all in the name of diligent preparation. "For about three nights before I go on the road I run through these voice routines an old opera lady taught me," explains the Moody Blues singer and guitarist, who enjoys the privacy and freedom a metal box on wheels affords this vocal assault. "I'm sure it's a bit of a bizarre experience if you pull up next to me at traffic lights." Making sure his voice is toned up is just as important as keeping the rest of his body fit and healthy for the man who has been fronting the British rock band for more than 40 years. Together with fellow veterans guitarist John Lodge and drummer Graeme Edge, who is still in fine fettle as the elder statesman aged 69, Justin is on the road in the UK next month, including a welcome return date at Plymouth Pavilions. A Swindon boy, Justin started out playing Buddy Holly covers in local bands from the age of 15. He joined the Moody Blues to replace Danny Laine in 1967, after answering an advert for a guitarist and singer in the Melody Maker, and has never looked back. The Moodies' talent for dramatic, sweeping, melodic rock, epitomised by their universally acclaimed anthem Knights In White Satin, has provided a rich back catalogue for them to plunder. "People are often surprised by us. They will hear a song and say 'I never knew that was one of yours," says Justin, who promises new additions to the setlist since the band were last in the Westcountry two years ago. Some songs work on stage better than others, so a recorded masterpiece won't always translate to the live arena. But the huge developments in technology over the decades helps to broaden possibilities. The Day We Meet Again, for example, is quite an obscure song from their 1978 comeback album, Octave, which they only played on stage a couple of times. "But we've rehearsed it up again and stuck it at the top of the show, and it works," says Justin. "It conjures up bittersweet memories really, because two guys left during the making of that album." He adds: "These days our problem is not what we should play, but what we could leave out. The show we are touring here is one we've already taken around the States, and I think there is something for everyone in there. "The first half includes some of the songs we did in the 1980s, like singles that were hits in America. In the second hour we play all the things we couldn't get off stage without playing." They make a big noise on stage, with the aid of a top-notch band, including flautist Norda Mullen who stepped in when Ray Thomas retired. An American who was brought up on the Moody Blues' music, she already knew every song inside out. Then there's Alan Hewitt on keyboards, Julie Ragins on backing vocals and percussionist Gordon Marshall. "We have always been a group that has adapted. In the 1960s and 70s we made records and we toured very little. Now what we want to do is tour," says Justin. He loves the gypsy camaraderie of being on the road, and starts getting twitchy after ten days at home in Nice, in the South of France where he has had a recording studio for many years.