'My profile's up, thank you very much'

He was 78, hadn't been in the public eye for decades, and he was suddenly front-page news. No wonder he was confused. The affair inevitably became known as Sachsgate. Jonathan Ross and Russell Brand had expected to have a telephone conversation with Sachs on Brand's Radio 2 show, but there was no reply, so they left a message. Egged on by each other, the message became increasingly offensive - at one point, Ross shouted out that Brand "fucked your granddaughter". They left three further messages - supposed apologies, at least as offensive as the original call - culminating with Brand musing about whether Sachs was not answering the phone because he was too busy thinking about killing himself after the humiliation they had heaped upon him.

Sachs's granddaughter Georgina Baillie responded by selling her story to the redtops, demanding an apology from Brand and Ross, appearing in bondage gear and revealing she had worked as a £110-an-hour dominatrix.

Sachs has clear memories of the story breaking. But not for the reasons you might expect. The previous night, his wife, Melody, had slipped in the bathroom and broken her hip. "She was whisked off to hospital. Major operation."

Next day, Melody was coming round from the operation, high on morphine. "The television was on, and she saw what she thought was me being hounded by paparazzi. She thought, that can't be right." She was convinced she was tripping. Meanwhile, Sachs barely noticed the fuss. He was more concerned about Melody. He hadn't heard the original broadcast, and had never given the non-interview much thought.

In October, he had agreed to be on Brand's show, but arrangements were confused. Brand rang Sachs's home number, but he was working on a Sherlock Holmes adaptation for radio and was waiting for Brand in a cafe with his mobile phone. A few minutes later, he received a call from a man he now realises must have been the producer, who played him some of the message that Brand and Ross had left. The cafe was noisy, and Sachs couldn't hear much of what they were saying, but he wasn't impressed by what he did hear.

He's trying to remember exactly what it was that startled him. "I thought, could I have heard that right? This is a bit odd. They mentioned my granddaughter Georgina, and Russell Brand said something like, 'I want to marry her'. I think it was the language they used. Jonathan Ross used the phrase, 'Go on, tell him you fucked his granddaughter.' I didn't hear that bit - if I had, I'd have thought I'd misheard it."

The producer asked if he was OK with the bit of the phone message he'd played him. "He said, 'Was that all right for you?' And I said, 'Well, it's a bit bold, isn't it? What I've heard of it - I don't like that.' And he said, 'All right, we'll see.' "

Sachs is remembering it more clearly now. "That's right," he says, "I said, 'Why don't I do it again?' Since it was clearly pre-recorded. I said, 'I could do it again on Monday when I'm free,' and the line petered out then. I just assumed they'd cut out the bits I'd heard."

Did he ever tell the producer he was happy with the message going out on the show? "No, I don't think so. No."

Sachsgate went viral. Even though there had been only two complaints after the programme was initially broadcast, encouraged by the Daily Mail, thousands more protested. There were even headlines suggesting that Ross and Brand could be imprisoned and repeated calls for them to be banned from the BBC. It grew into a debate about contemporary morality, humour, shock values, overpaid celebrities, the powerlessness of the producer, Reithian values and the purpose of state broadcasting. And at the heart of it all was the silent Sachs, who was too busy looking after his wife to respond, even if he had known what to say.

Did newspapers such as the Mail use him? "Oh yes. But that's their job. If they didn't, they wouldn't sell the papers. They don't lead the way, they play to their audience - this is what people want, give it to them."

Within days, Ross had been suspended by the BBC and Brand had resigned from Radio 2, as had the station's controller, Lesley Douglas.

In the end, Sachs says, the story probably proved most painful for Georgina's mother, Kate. "It was very upsetting for her. I'm not going to pry, but she feels very strongly. When the time's right, she can be more honest with us, but I'm not going to question her. It's for her to loosen up a bit."

We are sitting at a table in the Rovers Return on Coronation Street. The fictional pub is every bit as old and musty as it looks in the soap opera. Sachs, a small, dapper man with a gentle voice and a smile that transforms him into Norman Wisdom, is about to start a three-month stint in the Street as Ramsey, long-estranged brother of nosy Norris Cole. It's a role that Sachs part-invented for himself. Melody has always been a big fan of Coronation Street, and years ago she said to him, wouldn't it be great if Norris had an equally troublesome brother. "Bad enough to have one Norris, but to have two! Twins - Tweedledee and Tweedledum. I met somebody from the Street, producer or somebody, and we had a word - this was ages ago - and he said, 'I'll put that to them.'" Sachs never heard back. Two years ago, he was offered a part, but he didn't fancy it. He wrote back saying thanks but no thanks, but had they ever considered creating a brother for Norris? Last July, he was offered the part, but it was only in January that the contract was signed. "For the producers, all the publicity was just a happy coincidence." For the first time since Fawlty Towers, Sachs is back as a regular on primetime TV.

He is also writing an autobiography, which he started well before Sachsgate, and although it will take him up to the present, he doesn't expect Ross or Brand to play a prominent part. No wonder - he has had a fascinating life, not least his childhood. He has already written 40,000 words and has reached only 14 years of age. Sachs calls it a faction, then says, no, that's the wrong word. What he means, and this often comes up in conversation, is that memory is composed of what actually happened and what you think happened, or what you tell yourself happened, and soon enough all your realities merge.

What is certainly true is that he was born in Germany to a Jewish father and gentile mother. By the time he was three, Hitler had come to power. The young Sachs thought he was a fine man and an inspirational leader. "I was a fan of Hitler's. In primary school, my best friend, Ralph, and I, we had to go round the neighbourhood to collect scrap metal and empty toothpaste tubes for Hitler's 'peace effort'." He says he remained a Hitler fan until he saw early Charlie Chaplin films. "I switched allegiance. I thought, this man's funny, I never see Hitler laugh. He doesn't make any jokes. That's no good for me. Hitler had such a silly little moustache. My real hero became Joe Stalin. He had a real moustache - big enough for a young lad like me to swing on." He giggles.

He remembers how he and Ralph would go round collecting for the "peace effort" together, writing down the names of those who had donated and those who hadn't. Soul brothers, united in their cause. Then one day Ralph came and said he couldn't play with him any more. Sachs was as baffled as he was hurt. "I said, 'Why not?' And he said, 'My dad just says I can't. My dad says your dad is Jewish.' I said 'Yes.' And he said, 'Well, apparently Jews are not very nice to Hitler, so I'm not allowed to play with you.'"

In 1938, Sachs's father was arrested in a restaurant by an SS officer because he had a red J in his passport. Soon after, Sachs witnessed Kristallnacht, the horrific Nazi attack on Jewish people and their property. The family knew they had to escape. It was his mother who went around Berlin schmoozing and bullying the authorities to give her husband a passport, while Sachs's father lay low. "She had no fear of anybody. She's a bit of a hero of mine, as indeed is my father. She was pretty tough, and had a lot to deal with. God knows how she coped, God knows, trying to get out of Germany with a family and a husband who wasn't earning any money. He was an insurance broker, but it wasn't done to do business with a Jew."

The Sachs family arrived in north London when Andrew was eight. When he was 13, during the war, his father died. Despite all this, Sachs says he had such a happy childhood - he felt loved and secure and always had a roof over his head. Actually, he says, everything worked out for the best. Because he was so young when they came over, he learned to speak English without an accent. "If I'd come when I was 15, I'd have been left with a German accent, and if I had become an actor, I'd have been limited to foreign roles. So for that reason I'm grateful to Hitler."

Sachs started out as a character actor in the 50s, occasionally playing leads, but more often in supporting roles. He met Melody, a divorcee, in 1958, when he attended the dance classes she then ran. After they married, Andrew adopted her two young sons - Bill, who was six, and three-year-old John (who became known as a radio DJ and a commentator on the TV show Gladiators), and they had a daughter, Kate, together.

He appeared in any number of stage farces, but it was Manuel, the lovable loser from Barcelona, who made him famous. Sachs did bumbling haplessness with a grace that verged on the balletic. It was almost pure physical comedy - Manuel rarely said more than, "Si", "Que?", or "I know naaarthing", and was possibly the most physically and verbally abused character in the history of TV comedy. Fawlty Towers nuts will often turn up at charity dos or stage doors just to talk about Manuel. "We have little chats," he says. "I love it. They have pleasure out of it, and so do I. It brushes my ego nicely."

Why was Fawlty Towers so successful? "It's not only a farce," Sachs says, "it's a tragedy, and the relationship between all those people is very real. We recognise the follies in ourselves. It's exaggerated, but true to life. The other reason is technical - there was much more movement than in other sitcoms."

As for Manuel's popularity, that's simple. "You get a big man and a little man, and the big man always hits the little man... Well, the little man's always going to get sympathy, isn't he? It's like Laurel and Hardy."

After the second and final Fawlty Towers series (only 12 episodes were made), Sachs worked mainly on stage, radio and narrating for television. He last performed at the National Theatre in 1995, in Wild Oats. When he realised he had stage fright, terrified he would forget his lines, he decided it was time to give up.

But he always had a second, parallel career. Sachs has written more than a dozen plays, mainly for radio. The best known of these, The Revenge, is 20 minutes long and is composed entirely of sound rather than words. An adventurous cross between Pinter and the Two Ronnies, it won an award in, of all places, Barcelona, which pleased him no end.

In the past, Sachs would have always said that writing came second to acting, but now he's not so sure. Especially with an autobiography on the way. He's enjoying the stint in Corrie, but he is also looking forward to getting back to writing. "I'd put acting as a second choice now. In the past, I've always put my pen down to do an acting job. Now, depending on the acting job being offered, I'd be a little more careful to keep the pen in my hand." Have potential publishers shown more interest since Sachsgate? "Maybe."

Sachsgate has been awful for Melody and for Kate, Sachs says, but he knows that it has done him no harm. Quite the opposite. "I came out of it very well."

It has been great for you, I say. He nods. "Yes, my profile's up. Great! They did me good. Thank you very much."

You emerged from the sorry story adored, I say. He grins. "But I realised later that the reason the public were on my side was because of Manuel. He's the one who's loved. 'Poor little Manuel!' Don't you think so?"

He knows the papers made out he was terribly shocked about the revelations, but he never said that and nor was it strictly true. "I wasn't particularly shocked, because I knew what Georgina was doing, sort of. But there was a lot of misquoting going on. I didn't say much. People interpreted that as, 'He's so dignified.' I'm not dignified, I just didn't know what to say. What was there to say?" The shock was simply being in the news.

Is he close to Georgina? "No. She might say we were, but we aren't. I haven't seen her since or much before. She has her own life to lead, you know, and she knows we wouldn't approve."

He and Melody have written to her twice since the story broke, but they've heard nothing back. "She hasn't contacted us," Sachs says. "It's difficult. I think she's scared stiff of us. She can't cope with it. So she puts it behind her."

Does he think the publicity has been good for her? "She got a lot of money through whatshisname Clifford, Max Clifford." He comes to a stop. "I hope one day we might have a chat."

Back in January, there were stories that he would never watch Jonathan Ross again. Then there were further stories saying he'd watched his show and found it very funny. Sachs says he doesn't think he said either of these things, but he has certainly not banned Ross from his living room. "Well, I think he's got great talent. Although he talks too fast - so fast sometimes I can't understand him. He's got a very quick brain. If only he'd get rid of the other stuff, he'd be twice as good. But the sexual innuendo and the way he treats his guests is not good."

He says it's not true that Ross has asked him to guest on his show. If he did, would he go on it? "No, I don't think so."

As for Brand, he says he doesn't understand him. "I think he's aimed at a much younger audience than me." He pauses, rather elegantly. "No wonder he doesn't attract many of the more mature generation." And he leaves it at that.

A couple of weeks later, we speak and he's in good spirits. He tells me he's had an email from Georgina and he's just about to reply. As for the whole affair, yes, it has hurt those closest to him, but at least it has made people aware he's still around. And for that he's thankful. "Yes. Yeah. Well, I'm trying to sell a product, aren't I?"

• Andrew Sachs is in Coronation Street from 15 May.