GILBERT O’Sullivan prefers to look forward rather than backwards in a singer-songwriting career that stretches to 45 years.

Last year’s studio album Gilbertville was greeted with a review in The Guardian that said, “At his best, he is the missing link between the Kinks and Squeeze”.

Such a reaction would no doubt be music to Gilbert’s ears, as his interviews over recent years with York Twenty4Seven have highlighted his belief that his present is often ignored and his past is under-rated despite 13 Top 20 hits between 1970 and 1980.

Ironically, the focus is now falling on that past, on account of an 18-date tour to promote this month’s release of the career retrospective, A Singer And His Songs – The Very Best Of Gilbert O’Sullivan, that features Nothing Rhymed, Alone Again (Naturally), Matrimony and two number ones, Clair and Get Down.

He will perform those songs and plenty more besides with his 11-piece band, string quartet and all, on Wednesday at the Grand Opera House. On sale in the foyer bar will be the compilation that forms part of a reissue programme that may at last see the piano-playing Irishman receiving his critical just desserts at 65.

“I did a deal last year with Union Square, which involved them having the rights to my catalogue for about four years,” he says, on the phone from Jersey.

“During that time, subject to my approval, they have the right to exhume my back catalogue, release a greatest hits album and consider doing future compilations.”

Under the deal, Union Square/Salvo Records have already issued expanded editions of Gilbert’s 1971 debut album, Himself, and its 1972 sequel, Back To Front, each with extra tracks. Coming next will be 1973’s I’m A Writer Not A Fighter.

“I’d done standard reissues in Japan before, but this is the first time with extras,” says Gilbert.

“This time I had a music journalist, Chris Ingham, talking me through the album track by track for the sleeve notes, which was a learning curve for me, as I hadn’t done any research on any of these albums since they were first released.

“I had to learn again about what I’d written, what I was feeling at the time. I don’t really listen to my old songs when they’re gone, I don’t really have any interest in them, because writing new material lyrically and musically takes up a lot of time and energy and thoughts, so it’s a pointless exercise in a way to look back.”

His preference may be to move on from past deeds, but he still stores them with the assiduous mind of a librarian. “I have every recording I’ve ever made; I’m very mindful of everything I’ve written, other than two tracks that CBS own,” he says.

For the purposes of the reissue of Himself, Gilbert “went into his safe and looked into the vaults”.

“You get the very basic O’Sullivan, singing like an old man at the age of 19, and it encapsulates what was going in on my world at that time,” he says.

“My biggest influences when I started were Dylan from a singing point of view and Lennon and McCartney from a songwriting point of view, so I wanted to sound like Dylan singing Lennon and McCartney.”

He made an impression, how could he not, dressed like Charlie Chaplin’s tramp, being young but sounding much older on that debut record. It was a look that divided opinion and still does, but Gilbert stands by it, confident that the songs would win through.

“My philosophy is that you may not be as good as you think you are, but thinking you are is good,” he says.

“That’s the thing that gets you through the downside, and if you don’t think like that, the tragedy is that you will depend on what other people think and they will say different things behind your back.”

He believes he warranted the respect shown to Paul McCartney and The Kinks’ Ray Davies. “What damaged that was I didn’t look like the guys who were writing about me, so the image thing was the oil in the ointment, but I think the respect is gradually growing, and why not, for God’s sake?” says Gilbert.

“I’ve never striven to do more than write good lyrics and good melodies, and the way I get over the negative is that I continue doing what I’ve always done.”

Gilbert keeps striving to serve the rare gift of being able to write a great melody, now drawing inspiration from listening anew to Noel Coward and early Cole Porter. “Lyrically they’re very strong; musically they may be old-fashioned but you can be influenced by how good their melodies are,” he says.

Should he follow Porter into writing musicals? “I almost did a musical when I did my Rise And Fall album and we did think of looking back on my career with acting sequences and sections with me singing mainly my old songs but also two connected with show business after my court case [involving his former manager, Gordon Mills],” he says.

“Then in 1994 I wrote the album Every Song Has Its Play, which had more original songs about the business. But when people say I should do musicals, I just love the limitation of writing pop songs.

“Who knows, maybe someone will do a musical with my songs!”

• Gilbert O’Sullivan plays Grand Opera House, York, on Wednesday, 7.30pm. Box office: 0844 871 3024 or atgtickets.com/york

Did you know?

Gilbert O’Sullivan was the biggest-selling UK artist in the world in 1972.

His songs have appeared in the TV series The Simpsons and Life On Mars and been covered by Elton John, Bobby Darin, The Feeling, Nina Simone, Har Mar Superstar, Sarah Vaughan, Andy Williams, The Pet Shop Boys, Shirley Bassey, Tom Jones, Herb Alpert and… Morrissey.