A man of many worlds yet often at home in none, Lionel Blue, in his 75th year, has finally found equilibrium. ''One of the nice things about getting old is that you don't feel obliged to be successful,'' he says. ''And you don't have to tell fibs anymore. As my mother, in her nineties, told me before she died: 'Lionel, what's done is done, all the rest is gravy'.'' To this day Blue isn't entirely sure what she meant because his mother frequently spoke in riddles, but he thinks he understands the gist, gravy being life's bonus. Yet what did he mean by that reference to fibs?

''There were many years when I, being gay, had to tell lies because until 1967 (when the English law on homosexuality was changed), everything was so different. I remember horrific times when I was a kid, going through puberty and nothing could be said.'' That sense of being lost in a dark secret made for desolating loneliness, but perhaps it also shaped Blue's recognisable humanity - the holy man of folksy wit and wisdom who learned slowly and painfully that spirituality and sexuality were not polar opposites, but bound inextricably together.

By his voice many of us know Lionel Blue, a rumpled sort of voice, warm and humorous with Yiddish intonation and sometimes the only voice of vulnerability among the fluent certainties of his fellow contributors to Thought for the Day, that philosophical wake-up call on the Today programme just before the 8am news. Over the years thousands more, both here and abroad, have encountered him through his scholarship as a rabbinical and ecumenical teacher whose long and complicated journey from Jewish orthodoxy in the East End of London travelled through Marxism and Zionism and on to a rediscovery of God in a Quaker meeting-house at Oxford.

When Blue was a student at Oxford he had such a serious nervous breakdown he tried ''feebly'' to commit suicide. He was a precocious only child, ''a bright Jewish kid'', he says, who peaked before his time. ''I mean, I was an intellectual snob. I had a mind, but I had no body because I rejected it. And I had no soul because in those days I was a Marxist and didn't believe in such things. So I was working on just one wheel, my mind.''

Blue only cursorily discussed his homosexuality with his parents which again was typical of the time. ''In those days I suspected I was gay simply because now and then my father would read bits from one of the tabloids about men caught in court cases, and eventually I put two and two together. Then, of course, when I told them, they got worried but they were comforted that I still went out with girls. In fact, my deepest and lasting friendships have been with women.''

It's tempting to read Blue's newly published Hitchhiking To Heaven as an act of confession, although he worries that this suggests the book was propelled by guilt, and despite all those angst-ridden pages in Jewish fiction he doesn't believe Jews are inclined towards guilt in the way that it afflicts Catholics, for instance.

''I think most Jews feel that God has a lot of explaining to do where they're concerned. I for one used to be very upset and annoyed with God and the Cosmos because I had such difficulty in finding what I wanted, the person I could be with, that sort of thing.''

But Blue's memoir is no rant. Instead it is informal, engagingly meandering and good-natured rather than boiling with livid disclosure. ''The thing is I didn't want to use truth aggressively to hurt other people. There's a friend of mine who is writing his autobiography on the understanding that it won't be published until everyone in it is dead. Well, I haven't got that timescale, or that luxury.''

There is more than a hint here of mortality. Towards the end of the book, Blue writes: ''Heart problems, prostate cancer, epilepsy and a huge hernia - I've seen them come and go or get civilised. But a rare and rabid cancer may be one round I do not win. This is of course speculation.'' And on the morning of our conversation that speculation seems unnecessarily gloomy. In Blue's latest scans for the Merkel skin cancer, diagnosed around his last birthday, the disease appears unaccountably to have vanished.

Blue was raised in the tight-knit ghetto of the East End during the 1930s and 1940s when life in that community was so hard, fractious and confused it was often far too burdened to be convivial. Instead, it became, he says, a chaos of conflicting influences. ''There was the traditional Jewish world of my pious grandmother, the anarchist world of my grandpa, the Ginger Rogers and Fred Astaire world worshipped by my mother, and the secret world of my father's forays to a non-kosher pie and eel shop, his act of rebellion against the matriarchy that ruled our Jewish lives.''

But a wider and far more threatening adversity pulled disparate cliques together in these tough streets. Blue remembers that when the fascist leader, Sir Oswald Mosley, tried to march through the ghetto, tram drivers, tailors and factory workers - many of them Irish immigrant Catholics and atheists - joined forces with Jewish families to throw buckets of water over Mosley's blackshirts and his establishment protectors.

''Grandpa landed in jail, dad in hospital, ma made sandwiches and I was responsible for supplying mugs of tea. It was one of the happiest days in my childhood.'' A lesson, also, in how each and every one was seeking escape into an alternative reality from crushing poverty.

''Ours was a doomed world and the sooner we got out of it the better. It was too narrow, too poor, too limited and, without intending to, it destroyed people.'' Blue's own immediate answer was a rejection of a religion he had disliked since the age of five. But at Oxford this didn't help what he calls the Dostoevskian nightmare known to many in a severe depression. He had, he believed, three options: a living death in a psychiatric ward with ECT, a lobotomy or suicide. But one day in a doorway, sheltering from a rain storm, he found himself on the threshold of a Quaker meeting-house. No sooner was Blue inside than he heard his voice asking a deity - ''in which I didn't believe''- to make some sense of his misery.

''During that explosive testimony I surprised myself by thanking God for all my problems because suddenly I realised that without them I would be a self-satisfied prig or a sharp suburban solicitor. With them I could learn mercy, honesty and generosity.''

In time, Blue's exploration of Christianity and the torment of failed relationships led him back not to his original fold but to Progressive Judaism where, after graduating in rabbinical studies and ordination, he became European director of its world union. In his memoir Blue writes movingly about Jim, his partner for almost 24 years. ''I wasted a lot of time searching for my clone and then, through an advert, I found Jim, a Liverpool engineer. We've been in a faithful relationship ever since, two old codgers living very happily together, and none of my old recriminations against God anymore.''

Virtually, then, he's a rabbi in a gay marriage. Has that caused him the kind of problems causing such acrimonious splits in Christian churches? ''Well, the Orthodox Jewish tradition used to regard homosexuality as a terrible sin,

but now it's looked on as a

sickness. Progressive Jews, though, accept it as a reality in varying degrees and most try to find a blessing ceremony for couples which is inclusive.''

So, has he never been threatened with excommunication? ''No. But for 15 years I ran the religious court for the Synagogues of Great Britain which meant that I would have to be part of any excommunication machinery, and I've never been so masochistic as to excommunicate myself.''

Since the 1960s Blue has been involved in some of the most productive formal dialogue between Jews and Muslims. ''From the earliest I saw Muslims coming into Europe and they reminded me so much of my grandparents. One of the tragedies is that we post-Holocaust Jews haven't looked at ourselves and seen the refugee experience of the Palestinians in all of us. The Israeli establishment just thought the entire problem would somehow vanish in the sand.''

Today's rise in racism and anti-Semitism doesn't surprise him. ''Anti-Semitism has always been there, particularly in Eastern Europe, and now some of those countries my grandparents fled belong to the European Union. But because of the Israel situation anti-Semitism is strong on the left, not just the right, and we can't always be sure which side is fanning the flames.''

Yet, even in distressing times, Blue's faith in hope isn't diminished. ''I meet my congregation in supermarkets and trains, at the bar in theatres and through letters. Occasionally someone wishes I'd gone up in the smoke of the gas chambers but most people, radio listeners especially, impress me with all they go through in life.''

And if he is too wise a man to say for certain where truth resides, Lionel Blue, from his own testing journeys, has vivid memories of places where he's glimpsed it.

Hitchhiking To Heaven by Lionel Blue, Hodder & Stoughton, (pounds) 18.99.