The UK's television industry "risks becoming a victim of its own success" after a string of companies were bought up by giant US media conglomerates, according to Channel 4 boss David Abraham.
He said the arrival of large firms like MTV Viacom, which recently bought Channel 5 for £450 million, and the sale of scores of independent production companies was a threat to the system that made them successful in the first place.
One such firm, All3Media, which makes shows including Skins and Midsomer Murders recently accepted a £550 million offer from US firm Liberty Global which owns Virgin Media and US entertainment group Discovery.
Giving the keynote James MacTaggart Memorial Lecture at the Edinburgh International Television Festival, he said the UK's free-to-air channels had become "the must-have accessories, the tiny dogs of 2014, amongst US media companies".
Mr Abraham said: " I believe that it's the brilliance of how we, in this country, have balanced public and private risk taking that has set free the creativity and talent that the Americans are so keen to invest in."
Using the example of the 1990 BBC drama House Of Cards which was recently re-made to huge critical and commercial acclaim by streaming service Netflix, he said: " Would Netflix, for example, have bought a show about a murderous politician who broke the 'fourth wall' of drama if the BBC hadn't taken that risky decision, decades before?"
He said independent production firms were disappearing as they were being " snapped up almost wholesale and acquired by global networks and sold by private equity investors at a faster rate than tickets to a public flogging of Jeremy Clarkson".
Mr Abraham said those companies had succeeded in part because of " our unique 'PSB system' with its plurality of organisations and owners and its variety of missions and business models".
He said: " My second point is that this system now risks becoming a victim of its own success. While UK production is an undoubted commercial success story, I wonder if it will continue to be a creative one. Scale demands an increased focus on cost-cutting and margins. Reformatting ideas is more efficient than the messy business of finding new ones. Fear of risk overtakes an appetite for it."