Hosts Mel and Sue. Ian West / PA Wire/Press Association Images. All rights reserved.It took the independent production company, Love Productions, four years to persuade the BBC to try out a baking contest as a series idea. In 2010, "The Great British Bake-Off" (otherwise known as GBBO) launched on BBC2, inauspiciously, with an audience of some 2 million. It was a standard elimination show, with a weekly "star baker" and a weekly departee, but the excitement of seeing the ten contestants (12 these days) reduced to a final three, each week trying three different disciplines, one of them with no chance of preparation, slowly built the audience. By series three, GBBO was BBC2's most popular programme, and in 2014 it transferred to the main BBC channel, BBC1, where it also conquered all in the ratings battle, last year securing seven of the BBC's top ten audiences of 2015. Cooking and baking have a long history on British television, going back sixty years to the likes of Philip Harben and Fanny Cradock instructing BBC viewers on basic techniques. Such shows became staples in many countries, and some - like The Galloping Gourmet, Graham Kerr - were exported all over the world. Then came the competitions, like Masterchef, with skilled amateurs and semi-professionals tasked with producing complete meals. What GBBO brought to the genre was the emphasis on complete amateurs, and on the kind of elimination process that had generated viewer involvement in programmes like "Pop Idol", "Britain's Got Talent" and "I'm A Celebrity, Get Me Out Of Here". What GBBO identified was the chance to give contestants identical challenges, and sometimes identical ingredients, whilst allowing a degree of personal preference to be added to displays of technical skill. As the years went by, GBBO winners became minor celebrities, publishing books, writing columns, and exhibiting their skills at live displays. The most recent winner, Nadiyah Hussein - a diminutive, hijab-wearing housewife with a wonderfully expressive face - has even contributed two peak-time documentaries to the BBC schedule, about her return to her native Bangladesh. What has led many commentators to describe GBBO as "quintessentially British and BBC" has been the serendipitous casting of presenters and judges. The comedy duo, Mel and Sue, seemed odd choices as presenters to start with, being both inexpert and obsessed with weak (and suggestive) puns: but they have managed to integrate themselves seamlessly into the format, to surprising effect. The judges are a 40-ish blokey Northerner, Paul Hollywood, whose main expertise is in breadmaking, and 80-ish middle-class Mary Berry, with classic Home Counties locution, who has a long pedigree in cookery shows, going back many decades. Their expertise was hard to fault - as they have to demonstrate the technical challenges - and they also found a "good cop, bad cop" chemistry that has served them well.

The format for the Great British Bake Off has been sold to nearly 20 countries.Love Productions has had similar shows commissioned by the BBC, on sewing and pottery, but to much less effect. Meanwhile, the format for GBBO has been sold to nearly 20 countries, with the BBC version being broadcast by PBS in America; but two new US versions - on CBS and ABC, each using one, but only one, of the UK judges - failed dismally. Perhaps what is "quintessentially BBC" is not universally popular.

This is about to be put to the test. Some months ago, Love Productions announced that the current series of GBBO would be the last under the present contract with the BBC. Out of the current budget of some £7.5 million pounds, for the main series of 10 or 11 one-hour shows, plus multiple spin-offs, the production company probably earns less than £1 million in fees (supplemented by international distribution, format rights and repeats). It decided that it could demand £25 million for an expanded roster of programmes. The BBC declined to bid above £15 million. On Monday September 12th, midway through transmission of series 7, Love announced that, after a year of negotiations, there had been a breakdown. A few hours later, Channel 4 revealed itself as the new home of GBBO, having agreed to pay the asking price.

Remarkably, no-one at Channel 4 seems to have taken the precaution of checking with the presenters and judges whether they would change channels. Mel and Sue have already declared they would not switch sides, after the BBC had spent so many years nurturing the show. It is open to the BBC to approach Hollywood and Berry directly, and offer them enough commissions to match their current earnings from GBBO. As a long-term bet, without the risk of failure that a transfer to Channel 4 without the presenters might constitute, this could be attractive.

Before 1982, and the launch of Channel 4, there were almost no independent producers in the UK - the BBC and ITV simply refused to deal with them. Channel 4, as a publisher-broadcaster with no in-house production, suddenly found hundreds of companies pitching ideas. The success of the pioneers led to waves of talented producers leaving the old broadcasters, especially once they too had been required by law to commission at least 25% of their non-news output from "qualifying" independents (those with no shareholder owning more than 20% and also owning a broadcast business anywhere in the world).

This means that many of the UK's most popular programmes are owned, not by the broadcasters who schedule them, but by mini- or mega-capitalists, out to maximize the value of their creativity. There are now dozens of multi-millionaires who used to be staff or contract producers earning standard salaries. In the last decade, consolidation within the sector, and growing involvement by major US media corporations, has shifted the balance of power within UK broadcasting. "Qualifying" independent producers are now a minority. Channel 4 used to commission from over 500 of them. Last year, that figure was below 180.

Indeed, Love is 70% owned by Sky, making somewhat ironic its press release celebrating the fact that GBBO would be staying with a free-to-air broadcaster. But what Mel and Sue's snub has revealed is that the format alone is not sufficient to guarantee success. As the BBC discovered when it fired the lead presenter of "Top Gear" - so provoking his two presenter colleagues to resign - re-casting a long-established series is fraught with risk: this year's audiences were well below those for last year.

Re-casting a long-established series is fraught with risk.For the BBC, losing a ratings winner is annoying, but in political terms, being seen to reject prodigious financial demands could play quite well, what with the new Charter still not quite finalised. The obverse is true for Channel 4. Although in the past it has paid very large amounts to keep key elements in its schedule - "Friends", "ER", "The Simpsons", "Big Brother" - it has almost never tried to poach content from another channel (other than sport, where it bid strongly to win - for a few years - the rights to Test cricket and to replace the BBC as the terrestrial broadcaster for Formula One).

Channel 4 insists that its public service content is at a record level (by my calculations, a record low, but that is a different argument). That has not stopped its longest-serving Chief Executive, Michael Grade - now Tory peer Lord Grade - from claiming it has shot itself in the foot by spending so much money (£75million over three years) on another broadcaster's established show rather than on new creative ideas. He, of course, has been vocal in calling for Channel 4 to be privatised: its acting like a privatised company might weaken its defence against what seems to be a fading push for privatisation from the Conservative government.

Grade himself, of course, became famous many years ago for trying to seize "Match Of The Day" from the BBC when he was working for ITV. The headlines then were "Snatch Of The Day". This week, they are of GBBO being "poached", the BBC being "baked off", and Channel 4 possibly having "over-cooked" its deal. Because the BBC has a holdback clause in its contract with Love, the first GBBO Channel 4 can transmit will not be till late 2017. Its media rivals will, true to form, be anticipating failure - "knives will be out". Sorry! - Mel and Sue may have "declined the dough", but the puns will keep rolling on without them.