Emma, a novelist with two children, lives in north London - prime private-tutoring territory. Here, tutors are booked for years, their names whispered or withheld, while school gates thrum with news from tuition's front line - the kitchen table. 'It's the sole topic of conversation,' says Emma. 'Up here, a tutor is a fashion accessory. Drives me mad.'
Something has happened in tuition. About a decade ago, paying for a private tutor was seen as something to keep quiet about.
But over the past few years, Deborah Hogarth, marketing manager of tuition agency Fleet Tutors, has seen ambition trump embarrassment.
'I remember when hiring a tutor was considered an indication of failure,' she says. 'These days it's seen as positive, about children achieving potential. There's been a sea change in attitudes, and in private tuition itself.'
Somewhere along the line, that 'little bit of extra help' for your child became an industry and now there are many start-ups, larger companies expanding at about 10% to 20% annually and investment houses moving in.
For example, Explore Learning, with tuition centres across the UK, was bought by its management and a private equity firm last year for about £30m.
The UK appears to be following the example of Japan, where for many years private tutoring schools have been listed on the stock exchange, and where tuition is an integral part of the education system.
And why not? Tuition is cheap (usually between £20 and £60 an hour and, dare one say, often tax-free). No wonder it's booming. In 2009 (the most recent data) NatCen/IoE counted 504 tuition agencies. That's on top of sole traders who are still the bedrock of a market that is essentially a huge cottage industry.
Tutoring runs from personal ads in newsagents' windows, through local agencies where tutors are sub-contractors, to international companies like Kumon, which started in post-war Japan and now operates a global franchise model.
It's vast, amorphous, still mostly driven by word of mouth - and people are starting to realise that it can be very good business.
Still, in the UK, the drivers are often negative. Anxieties among parents, perceptions of ungovernable classes and teaching deficiencies in state schools, tougher competition in a depleted work environment: these are all contributing to tuition's steep growth.
The recession has sharpened the debate, but, meanwhile, expansion continues. The education charity the Sutton Trust found that 18% of UK children received private tuition in 2005, rising to 23% by 2011-12.
It's particularly strong in the hothouse of the south-east. In London, 38% of children now receive private tuition.
The UK market has been estimated at £6bn a year and to employ, on and off, one million people, with an average spend on each child of £2,758 per year.
'It's impossible to know the extent,' says Hilary French, president of the Girls' Schools Association and head of Central Newcastle High School. 'But it's big - and a big issue.'
Still, this huge, often grey economy is utterly unregulated, which is why think-tank the Centre for Market Reform of Education (CMRE) is launching The Tutors' Association this summer.
About time, says CMRE director James Croft. 'Tutors come in all shapes and sizes,' he says. 'The industry needs a code of ethics, minimum qualification thresholds, a guarantee of good standards, and a kite-mark-style logo - just as already happens in the US and Australia.'
It will also make tuition even more business friendly.
Croft is not calling on the state ('We want voluntary self-regulation') but says the TTA will give shape to a messy industry.
'There's a lack of clarity about tuition and what it should be achieving,' he argues. 'Tutors and their clients need help: not just to assure good tutoring, but to guard against overtutoring.'
This year, he says, will be remembered as the year when private tuition matured.
At present, most tutoring agencies are still local, with a handful of tutors on their books. A few are national, such as Fleet Tutors, with 10,000 students, 7,000 tutors - and 20% annual growth. Other big names include Bonas MacFarlane, Bright Young Things, Enjoy Education, Keystone Tutors.
Nevil Chiles of Kensington & Chelsea Tutors has been in the market for 10 years. 'We have 2,500 tutors and are growing by 10% to 15% a year,' says Chiles. 'We see 40 tutors a month. That's an interview a day. Hard work.'
Tuition firms are mostly still 'employment agencies', says Croft, but they're becoming more like consultancies, with expertise, branding, marketing and particular strengths.
'A business equivalent would be estate agents,' says Malachy Guinness of agency Bright Young Things (BYT). 'It's a more professional business environment now, with differentiation.' And there's a growing international dimension, with travel, e-tutoring and Skype tutoring on the rise. 'Tutoring is growing everywhere, particularly the developing world,' says Guinness. 'We think the UK has a chance to lead this global market.'
Indeed, and perhaps it's time we celebrated this emergent industry. 'Tuition is a real UK success story, which other countries recognise,' says Kate Shand of agency Enjoy Education [Shand is also one of our 35 Women Under 35]. 'Now our Government should get behind it.'
As you'd expect from a growth industry, new people are increasingly entering the fray, possibly because of graduate unemployment. 'We came in three years ago and competition has become fierce,' says Alastair Delafield of west London-based Ivy Tutors. 'People have seen there's a boom. They want in.'
So there's a rush to market, driven partly by what Shand calls 'a low barrier to entry. There are so many start-ups around. But there's a credibility gap, and it's fragmented.'
Hence Croft's TTA, which aims to bring a bracing professionalism to the nation's kitchen tables.
So, what of the tutors themselves - are they ready for the new mood of professionalism? The classic tutor remains a graduate or post-graduate.
This noble pedigree includes James Joyce, WH Auden and Christopher Isherwood - tutors all. My son was tutored by a lovely Oxbridge graduate called Claire who knew maths. She was also a Shakespearean actor.
Novelist James Miller is in this tradition. 'I was living in London, doing a PhD, needed money so started doing Common Entrance and A level tuition. It made sense.'
Indeed, he still does it, but only for '£150 for two hours minimum'. He turns clients away. 'You could do it all your life. Some do.'
There is a growing tier of long-term pro tutors, but most still treat it as temporary, as a way of getting supplementary money. 'Ours tend to go into the City after tutoring,' says Guinness, himself a sponsor of the TTA.
Guinness has also helped develop a proprietary software called Tutorcruncher to help the industry grow, which he hopes will be the leading tutoring software in the world. 'Tutors spend ages doing the admin and invoices, which has kept the industry back. Without planning, it's a blizzard of text messages.'
In tandem, parents' motivations are changing. Tuition used to be for children struggling with a subject, cramming for a school or towards exam.
Now, says Shand, tuition is more like a vitamin supplement: 'About giving children their best shot all the time.'
So traditional reasons for private tutors, such as better exam results, have been joined by other scary factors: future employment prospects, gaining competitive advantage, even improving bad teenage attitudes.
Tutor Amy Campbell Golding, an ex-teacher with Ivy Tutors, specialises in undermotivated boys. 'I'm called when there are problems with behaviour,' she says. She's busy.
The tuition boom affects both the state and independent sectors. In the former, it's often taken on to stem perceived deficiencies and is sadly necessary, says London tutor Phil.
'The bald truth is that some schools aren't doing their jobs properly,' he says. 'I'm principally a maths tutor and I daily see clearly discernible deficits. Many students coming up to GCSEs cannot even divide.'
So parent are right to be concerned? 'Yes.'
Thus tutoring raises the game. It's even seen as a magic bullet.
As Janette Wallis of The Good Schools Guide has said: 'The unseen story behind ... comprehensives getting stunning exam results is how many parents at these schools use tutors.'
And now, the middle classes are being joined by lower-waged immigrant parents. 'They all really want their kids to succeed,' says Phil. 'Foreign-derived parents don't have the same angst around private tuition.'
In the independent sector - and despite the fact that parents are paying twice - tuition occupies an even greater market ratio, fired by the Common Entrance exam at 13 and competition for places.
About 60% to 70% of Kensington & Chelsea Tutors' clients are from private schools; BYT exclusively so. 'That's the irony,' says Miller. 'The kids that don't need it are getting it, while the kids that do aren't.'
So the wider tuition trade is bullish. But even as it booms, forces are mustering against tuition, with criticisms dividing between the educational and the social.
Variously, it is seen as undermining the authority of schools, lacking quality control, running counter to curricula - even 'stealing' childhoods.
Ben Thomas of Thomas's school in Battersea, has accused tuition of 'devouring' free time and masking innate abilities.
'The vast majority of heads are not in favour of private tuition,' confirms Barry Sindall of the Grammar Schools Heads Association. 'It creates pressure for children and is really about parental anxiety.'
Some tutors quietly agree. As Phil says: 'It's true that there has been a huge increase in competitive pressure, especially since the recession. Expectations for year 10 (14 to 15 year-olds) are now applied to year nine.'
Phil recently refused to tutor a year three pupil (seven to eight year-olds). 'Crazy. I told the parent I wouldn't do it until year five.'
Many British teachers would ban tuition. 'Well, I'd discourage it on principle,' says French. 'We should be meeting educational needs. Tuition suggests we're not doing our job properly.' Plus, she adds, tuition masks other important values.
'Will tuition and cramming help us get the creative, problem-solving individuals that I'm always being told we need? I doubt it.'
Some hope to design private tuition out of the system; others to harness it to egalitarian ends. Sindall cites the Bishops Wordsworth's School in Salisbury, which offers private tuition in-house to raise money to pay for tuition for deprived children.
In September, Chelmsford County High School for Girls is introducing a system to stop 'middle-class parents subjecting children to six years' worth of coaching in preparation for the admissions test', as head Nicole Chapman put it.
Most notably, Kent Education Authority is to ban tutoring for its grammar schools. 'There's a growing educational movement trying to be tutor-proof,' says Croft.
Even so, those in education whisper that schools operate double standards, basking in their pupils' new successes while outwardly spurning tuition. 'Outwardly, external tuition is not encouraged,' says a London prep school teacher, Dick. 'But senior schools expect it.'
This imbroglio feeds mistrust between schools and parents. Clarissa Farr, high mistress of St Paul's Girls' School, asks parents to declare tutoring - her premise being that tuition is an 'industry which trades on insecurity and exam anxiety, sometimes undermining rather than building confidence.' Indeed, she wants a charter requiring all tutors to register with the school.
And, for sure, some parents are at fault, outsourcing their own duties.
'I remember one poor child,' says Miller. 'After school every day he had two hours' tuition, then four hours every Saturday. He was bored shitless. Terrible. Counter-productive.'
Emma, the north London novelist, now regrets tutoring her son at 10. 'I worry that I wrecked his childhood. I should have let him play football.'
Much parental motivation lies in FOMO - the fear of missing out. 'It's a race,' adds Emma. 'You've got to keep up with the Sophies and Jacks who are all doing "really well", of course.'
Agencies refute these notions. 'Stealing childhood?' says Shand. 'Education is a great gift. Holidays are long. Tuition decreases pressure on kids by alleviating stress and navigating them through a complicated system.'
As to the social divisiveness, says Hogarth at Fleet Tutors: 'I wish you could read our testimonials. Tuition boosts a child's performance, self-esteem and social mobility.'
Tutors are taking advantage of their industry's raised game. 'For a good tutor, 50K is now quite ordinary,' says Guinness. Amy Campbell Golding 'earns more than I ever did as a salaried teacher'. And there's even a tier of 'super-tutors' who command big sums, such as BYT's Topes Calland, who charges up to £400 an hour to London's international rich.
The market is ratcheting up for these tutor stars, says Guinness. 'They're like butlers, benefiting from the UK's educational mystique.'
Miller thinks that much private tuition is driven by status. 'It's very snobby,' he says. 'It's all about getting an elite person. Parents are obsessed by Oxbridge. It's about gaining some cultural capital conferred by the English educational reputation.'
Also, some parents seem to want a kind of life mentor-cum-status symbol around the house. 'Sometimes you have to be the big brother or a glorified babysitter,' adds Miller.
Delafield adds: 'People want tutors who are young and cool. The parents see them as the missing piece in their jigsaw.' The absurd pinnacle of tutor envy was reached in 2011, when it was reported that Chris Martin and Gwyneth Paltrow were seeking a super-tutor who would teach Apple and Moses Ancient Greek, Latin, French and Spanish - and play two instruments, play tennis and sail.
Two decades ago, I was a tutor and worked in a world of scrunched paper and stained coffee cups. Now in an uncertain and globalised world, education offers new anxieties and commercial opportunities.
'Tuition is one of the great educational resources of the country, which the Government should take heed of and harness,' says tutor Phil.
As its confidence has grown, the tuition industry has thrown a huge privatised gauntlet at the educational establishment - and a showdown or accommodation is inevitable.