In the 1970s, flat-capped crooner Gilbert O’Sullivan had quite a reputation.

Seen as something of a thinking man’s Elton John, or a modernised lyric-writer aping Randy Newman, O’Sullivan delivered snappy pieces of melancholy pop with poetic twists, cleverly touching off issues like poverty and heartbreak all at the same time.

19 albums later, and O’Sullivan’s back in the limelight: his new self-titled release has been BBC 2 Album of the Week, won broad critical acclaim, and seen the Waterford-born singer – raised in the English industrial town of Swindon – enjoy something of an Indian summer.

Beneath the pop melodies and affecting love songs, O’Sullivan’s always had a bit of a political bent, as it happens. It’s unchanged in years, and like his songwriting, the best of it is quite indirect, obliquely leaning on politicians, or directing eyes to injustice.

After nearly 50 years in the business, the 71 year old certainly knows the impact of his songs, however. ‘We Will’ is one of the great takes on personal darkness. He also has the subtle cultural attack and gentle poetry of ‘Nothing Rhymed,’ and the brilliantly gentle ode to loss ‘Alone Again, Naturally’. O’Sullivan has affected much, but, in terms of songwriting, he’s little changed.

“I follow the same process I always did,” he tells us. “I write the melody at my piano. In the past, that was a dirty old stand up and it’s a bit better now, but I still do it the same way, recording the music onto a boombox as I go.”

“I don’t add the lyrics until I come to record a song. For this album, I had all the music, but spent two months writing the lyrics before I went into the studio. I had played through the music for the record company, BMG, just singing whole-hearted gibberish over the top, to check they wanted to be involved.”

“The lyrics come last because they’re always changing according to the time. Once they’re recorded, they stay the same, but before that they keep evolving. I often have two or three different versions of a line going into the studio. Otherwise, lyrics can be out of date.” He now has his own personal studio in Jersey, the only high-end one on the island, where the most recent record was recorded.

O’Sullivan left Ireland as a youngster, but still feels a close link when he returns. Sitting in a Dublin hotel, he tells us he feels a “special connection” with the country, and is sometimes told he still has an Irish accent, the same as his mother.

“The exposure in England has been really positive, but I’m really proud of my Irish roots,” he says. “I came back a lot as a student. It’s changed a lot, but I love it as much as ever.”

As for the future? “Things are going really well right now, and I can’t really imagine stopping while it’s like this,” O’Sullivan explains. “I’m in the heart of things. This is my most successful album, probably, since the 70s, and I’m really enjoying doing all the shows around it. I’ve had my first UK top 20 since 1974. I’m in a good place.”

Gilbert O’Sullivan’s self-titled 19th album is out now.