The film is based on Slater’s bestselling memoir, Toast: The Story of a Boy’s Hunger, which tells of how Nigel, born in Wolverhampton in 1958, was starved of affection after his mother’s death from asthma when he was nine. There was more tragedy when his father, who owned a factory making parts for Rover cars, died of a heart attack eight years later. But this was no great loss, as Slater didn’t like him; and he hated his stepmother.  Life has clearly worked out well because Slater is now something of a national treasure: a skilled broadcaster and journalist who has managed to convince us that cooking need not be a fraught, perfectionist struggle. But what a grim childhood. ‘He has remarkably managed to make something very special out of quite bleak beginnings,’ Lee Hall says. ‘It would have crushed most people.’  The film opens in the summer of 1967, with Nigel and his mother in Percy Salt’s, a grocer’s in Wolverhampton. Nigel is gazing at pork pies and hunks of caerphilly and cheddar cheese arranged in glass counters. But Mum, a sensitive soul with tidy habits, is averse to fresh produce. Her idea of cooking is putting three tins into a pan of boiling water: braised beef, processed peas and new potatoes.  Nigel is a born foodie, desperate to eat things that actually taste of something, but it doesn’t matter: his love for his mother is nourishment enough.  The irony bites deeper when Dad, remote and bad-tempered, falls for Mrs Potter, who lives on a council estate, wears Crimplene and is a fabulous cook. She bags Dad with her apple pie and plump trouts. The film charts how cooking saves Nigel, first as a way to replace affection and get back at his stepmother, and then as a ticket to a new life in London.  ‘At its core it’s about a little boy trying to find love in an unloving household, and that is such a universal thing: feeling like you don’t belong,’ Clarkson says. ‘Also I find it incredibly powerful that the mother he loved so dearly is absolutely rubbish at cooking and a bit frightened of it, while the stepmother, whom he despises, is just the most phenomenal cook.’  Ruby Films first bought the rights soon after Toast was published in 2003, and approached Hall to write the script. At first Hall, who was Oscar-nominated for his screenplay of Billy Elliot, was ambivalent. ‘It was territory I had covered before, but then I realised it was simply too good to pass up, so that is why I signed on. Obviously it’s about food, and it’s about coming of age, but it’s also very much a drama about loss.’  Hall’s approach was to lighten the story – ‘it’s joyous that Nigel becomes a cook and finds his independence, but it’s quite dark and it’s quite bleak in a lot of places’ – and he pared down the family. Nigel’s two older brothers and Aunt Fanny, who lived with the Slaters, have been erased. ‘What is beautiful about the book is it’s so fragmentary – it hasn’t got a narrative, as such,’ Hall says. ‘I had to piece together something that was going to look and feel like a drama so, yes, I did simplify it. I was trying to get to the core of the emotional heart of the story.’  For the next few years the producers tried and failed to get it made. And then in January this year they received a call from the BBC. ‘It was Ben [Stephenson, the controller of drama commissioning] and he said, I have to do this, I really love it,’ Faye Ward, the producer, recalls. Toast went into pre-production at the beginning of March, funded by the BBC and Screen West Midlands, and the five-week shoot began in June.  Slater himself was ‘much more involved than I ever intended to be’. He advised on small details – his father’s aftershave, his mother’s poppy dress – and even appears in a small cameo role: ‘I thoroughly enjoyed it.’  Back on set at the farmhouse, a 20-minute drive from Birmingham, Helena Bonham Carter, wearing an eccentric, pistachio-green straw hat, is chain-smoking on a sun-lounger while the crew plants marigolds and daisies to create an instant cottage garden. But really they are all focused on the catering truck, which today is serving braised lamb shank, smoked haddock and spring onion fishcakes, lemon bread and butter pudding, and toffee crunch pie.  ‘I have never eaten as much as I have on this job,’ says Clarkson, whose directing credits include Ugly Betty, Mistresses and Footballers’ Wives. ‘When you are reading the script you get hungry, when you are shooting it you get hungry.’  The other surprise is that Clarkson – whom Ward describes as robust and not at all the sort of woman to spend hours in the kitchen – has started baking jam tarts and shortbread for the crew. ‘Maybe in some way I was being very method as a director, but when you bake for somebody their reaction is extraordinary,’ Clarkson says. ‘It is very powerful.’  Then there are the 1970s props, which are having a profound Proustian effect. ‘Arctic Roll!’ exclaims Helena Bonham Carter, who is taking a break between scenes, scanning the Slaters’ pantry.  ‘I haven’t thought about Arctic Roll for years. I remember going to Bejam with Mum on a Friday and getting Arctic Roll; that was a real treat.  ‘It’s so bizarre,’ she continues, surveying the box of 1960s Ricicles (with a picture of Dougal from The Magic Roundabout) and the butterscotch Angel Delight. ‘My whole childhood is here.’  She says that being in the film has made her think about what she feeds her own children (she has two with the director Tim Burton, Billy and Nell). ‘I’m trying to shove them things now, thinking, “This is nostalgia, this will give you happy memories”, and so I do things like cook them fantastically warm toast and make bread. But they couldn’t be less interested. All they want is crappy white stuff, and I’m thinking, “Look, I’ve made you a memory for Christ’s sake”.’ She laughs. ‘Rejected memories!’  Fans of 1960s fashion will admire Mrs Potter, with her desires spilling out of her minidresses. Whereas Victoria Hamilton’s Mum is aqua and soft with a small waist and delicate brooches, Bonham Carter teases in housecoats, busty dresses and suspender belts (her seamed stockings are originals, bought on eBay at £21 for three pairs).  ‘Actually suspenders are not as uncomfortable as I thought,’ she says, ‘although it’s always a shock to sit down on a plastic chair. You also feel somewhat naked and unprotected. Mrs Potter used both her cooking wiles and her sexuality.’ The camera makes lots of wonderful slow moves on Mrs Potter, watching her wicked allure unfurl.  Bonham Carter says she wanted to play Mrs Potter because she loves people who are ‘complicated, not immediately unsympathetic and probably somewhat ill mentally.’ She suspects Mrs Potter’s manic cleaning was a symptom of obsessive compulsive disorder, and says it was a challenge to ‘look vaguely credible with the cleaning. I’ve never cleaned much before. My mother says she is still waiting for me to develop my domestic aspect.’  Julie Walters, it transpires, helped her with the Wolverhampton accent, while Nigel Slater took care of the details: Topaz perfume, red lipstick for going out, and ‘she did emery board’.  The other attraction for Bonham Carter was being reunited with Freddie Highmore. They first met on the set of the film Women Talking Dirty when he was six (he is now 18 and in his first year at Cambridge University) and were also in Charlie and the Chocolate Factory together five years ago. ‘He is just such a touching actor,’ she says. ‘Really bright without being precocious and he never demonstrates as an actor – he always just is. It’s quite hard to be horrible to him.’  Highmore finds a balance of melancholy and sweetness in his role and is also convincing in the kitchen. It is his task to exemplify Nigel the burgeoning cook, and this is done in close detail: boiling potatoes for shepherd’s pie in domestic science; piping rosettes of meringue for the lemon meringue pie (a dish that becomes a lethal weapon, as Nigel competes with his stepmother to come up with the best version for Dad).  ‘The thing that attracted me [to the role] was his relationship with Mrs Potter,’ Highmore says. ‘The way he hates her as a person, and the things she stands for, but actually loves her food.’ He also likes the period nature of the film, but has been slightly taken aback by the consequences. ‘I have these black pumps as part of my school uniform and everyone keeps coming and saying, “Oh my God, I used to wear those!”’  ‘It is really weird,’ echoes Oscar Kennedy, 11, who saw off competition to play the younger Nigel, despite having acted only in a local drama group in Nottingham, and delivers a penetrating, uncute performance. Today Kennedy is resplendent in a 1970s brown Fair Isle knit (modelled on Slater’s original) and itchy wool shorts. ‘A lot of adults are saying, “I used to have a jumper like that.” It does feel strange.’ Both Highmore and Kennedy are too young to relate to such cries of lost youth (or to Cadbury’s Smash). ‘But it's obviously all about unlocking memories in the way Nigel does in his book,’ Highmore observes.  Clarkson certainly keys into this nostalgia with the camera hungrily taking in a Fray Bentos billboard and the rows of Caramac bars in Percy Salt’s. But rather than nailing down Slater’s childhood into something tight and gritty, her aim is to create more of a ‘magical fairy tale’. Her references include Terence Davies’s The Long Day Closes; Amelie (‘for the fairy tale’) and My Life as a Dog (‘for the child’s point of view’). Cameras swoop, zoom, are positioned at the back of ovens. There is a dash of slapstick in a montage of Mrs Potter putting down dish after dish – toad in the hole, roast chicken, bananas and custard, Victoria sponge. ‘The camera moves are expressive and that gives you a more heightened feel,’ Clarkson explains. ‘It’s about telling the story through a young boy’s perspective.’  Tomas Burton, the production designer, has also done something cunning with the colours in the farmhouse – the browns and oranges on the looming walls making everyone feel oppressed. But there is another reason behind the film’s drab palette of greys, greens, browns and creams. ‘We really pumped up the colour of the food so that it would stand out,’ he says. ‘Food is the hero of the film. It’s all about the food.’  Katherine Tidy is a home economist and food stylist who has worked on films including Pride & Prejudice, Atonement and Pirates of the Caribbean 4. ‘I’ve done a lot of films where I tend to work a day here and a day there,’ she says. ‘On Toast I was there for a whole month.’  Her output included 30 lemon meringue pies (for the various takes), ramped up to toxic levels with yellow food colouring, plus a sweep of some 40 dishes for the wedding reception: pineapple and cheese on sticks, vol-au-vents, ham with glace cherries and pine­apple slices. ‘It was all very kitsch.’ The roast chicken on green mash was inspired by Fanny Cradock. ‘Yesterday we had a very long conversation with the art department about how you open a can of Spam,’ Faye Ward says. ‘You have very surreal moments with nostalgic food.’  So, what does Nigel Slater himself make of it?  ‘I became quite divorced from little Nigel when I was writing the book, because he was such a long time ago,’ he says. ‘I think I almost felt I was writing about somebody else. I had this incredible knowledge about him, but actually he was another person. But then I just happened to walk on set on the day they were shooting the most emotional scene imaginable. [Mum, breathless and close to death, tries to make mince pies with her son.] I suddenly realised absolutely it was my story and it was me, and there was a moment when Oscar was with Victoria that was just so like it was. Then I’m afraid the tears came flooding out. For the first time, really, I was taken back to that moment.’  ‘Toast’ is on BBC1 on December 30
Toast, Nigel Slater&rsquo;s memoir of a grim childhood leavened by his love of food,   is being served up on screen