there are a number of ways to leave a soap opera. Kidnapped by aliens, feet first via a hail of bullets or a gruesome garlic press accident, even out the back door, as in the case of "Poison" Ivy Brennan's infamous get-thee-to-a-nunnery exit from Coronation Street. But few leaves have been more gladly taken than Thursday night's departure, head held high, by original EastEnder Michelle Fowler - 'Chelle, to give her her formal title - gone to a new job and a new baby in the New World.

Given that she has, in the Albert Square vernacular, a Grant Mitchell- shaped bun in her oven, Walford will breathe more easily without her. But if her new life in Alabama doesn't work out, she will always be welcome back. As the grittiest, feistiest fixture in a British soap landscape whose younger female inhabitants are increasingly required to be boy's magazine pin-ups and little else, Michelle Fowler will be sadly missed.

Susan Tully, 'Chelle's amiable and soft-spoken earthly embodiment, sips tonic water in the palm court room of the Langham Hilton. She is not going to America, but to Hull. She starts rehearsals in a few days for a late November opening with John Godber's Hull Truck Theatre company. After 10 years in EastEnders, and a few weeks of being unable to go to the shops for a pint of milk without seeing her face emblazoned across the front cover of every TV magazine, it must feel strange to be slipping out of the public eye. Tully smiles and slips easily into a stage whisper: "It's bloody great."

Fond though her last look round the Albert Square set was, Susan Tully was more than ready to leave. "When I was younger [she is 28 now], I had this naive thought that I would be in EastEnders and someone would say 'Look, we've got this thing for you'. Ten years went by without that happening, and I began to realise that I didn't want to be in EastEnders when I was in my 30s." What would be so bad about that? "Nothing, but one day I'd like to have kids, and I would like to bring something to their upbringing. I'd like to have lived a bit, done a few different things."

What these things might be, she still isn't quite sure. "One of the casualties of being in work for so long was that I didn't really form many ambitions, but I'm starting to now. I know I don't want to end up in the top right hand corner of Celebrity Squares." The world's most well-adjusted child star, Tully has been a small screen regular since she was nine. She didn't come from a showbiz family (her dad was a watch-case maker, her mum a housewife) but going to the Anna Scher children's theatre as a change from Brownies and swimming turned out to be the fast track into TV.

From Saturday morning kids shows she soon moved on to shine - along with Todd Carty, aka Michelle's brother Mark in EastEnders - amid the first intake at Phil Redmond's generation-defining Grange Hill. At real school in Barnsbury, Islington, meanwhile, she "acted being normal". This, as her subsequent career has indicated, is something Susan Tully is pretty good at. "I used to deliberately get myself into trouble," she remembers. "I was quite bright as well and I didn't want to be seen as a goody two shoes, so I started smoking really early to get in with all the hard girls. I was the only one who could afford a packet of 20, so that helped. 'Don't beat me up, have a fag.'"

She had left Grange Hill and was about to go to sixth form college when EastEnders came up, ushering in a couple of years of top-flight celebrity hedonism. "I was 18 and I was earning a stupid amount of money: it was party time - complete mayhem." Rolling around in the gutters outside Stringfellows, that sort of thing? "Yes, I'm sure I've been there - 'Stop the cab, let me puke and then we'll carry on with our evening' - it was fun but I'm glad I grew out of it." Forsaking the high life for an Open University degree and a flat in Muswell Hill, Tully seems to have had little trouble keeping showbusiness and reality apart.

"There's a saying you hear on the set all the time which is 'I don't think my character would do this'. Whenever that thought pops into your head, you have to work out whether you're talking on behalf of your character or yourself. Sometimes your ego doesn't want you to do something which might actually be very true to the character, because it portrays them in an unsympathetic light". Presumably in order to play Michelle, who has done her fair share of unsympathetic things over the years, you'd need to be pretty well inured to that?

"I think it helped that I was only a kid when I joined. Because I didn't have any clout whatsoever, I knew I was the property of the writers - it wasn't my character, it was theirs - I was just lucky they made her such a joy to play." What was it about Michelle that made her age like a fine claret? "You know how you get these words in your head and you think 'If I say this it could be the wrong word and I'm going to look completely stupid'. Well, there was a dichotomy about Michelle. On the one hand you have this character who's the girl next door - dependable, loyal, a bit predictable; someone who will tend to take the middle road. But every now and again she'll just go off on these complete tangents and be totally reckless."

Why did she do that? "She loved her mum but she didn't want to be like her - I suppose a lot of people could relate to that - so whenever she felt she was getting too close ... wallop! She'd be off. That's why I never said 'I don't think she'd do this', because I didn't know what she would do. Everybody's thought at one time or another 'how on earth did I get into this situation' - you don't really know what you're capable of until you do it." Maybe, but to convince the audience that you are capable of a one-night stand with Grant Mitchell is a significant achievement.

Though she was delighted with how the story finally turned out, Susan Tully admits to having been "very concerned" when she found out that her long-standing enmity with Walford's answer to the abominable snowman was to be sealed with a kiss. "People can get together for all sorts of reasons - out of boredom, out of mutual consolation, out of love - so I didn't have a problem with that, but the mechanics of it worried me. I was worried that they'd go down the 'no means yes' road: it might've come out of the middle of a heated row, where it almost gets violent and then she crumbles into his arms like in some awful B-movie."

That wouldn't have been a very 'Chelle-like thing to do. "Not really. If anything it would've been the other way round - she would've beaten him around the head until he succumbed." From Dennis Watts to Grant Mitchell via Lofty Holloway and that polytechnic bloke, Michelle certainly ran the gamut of masculinity well beyond A to B. But she left Albert Square defiantly unhitched: John Redwood's worst nightmare - the successful single mother. If the polemical intention of her triumphant departure was obvious - the road to 'Chelle was, after all, paved with good intentions - it is greatly to Susan Tully's credit that its resonance was undiminished.

She doesn't know how her next part is going to turn out yet, but she is optimistic. John Godber's play The New Office Party is set in a Northern advertising agency. Susan Tully's character is "different enough to Michelle to be worth doing, but not so different as to scare me to death. And she's a Southerner, so I won't have to do an accent." She grins, perhaps with an eye to any casting directors who may be reading, "I can do them though."

8 'EastEnders' omnibus, BBC1 1.30pm today. 'The New Office Party' is at Hull Truck Theatre from 29 Nov to 13 Jan (box-office: 01482 323638)