Thompson, who spoke for just over an hour at the Edinburgh International Television Festival, argued that a properly funded Channel 4 was needed to champion creative standards, claiming that a publicly owned Channel 4 remains the best option, backed by taxpayers' support if necessary.
He said: "We don't expect to call on public support over the next few years. Indeed we may never do so. Channel 4 should always aim to pay its own way. But if changes in the broadcasting landscape mean we have to choose between financial survival and our public service remit, then the case for public support will be overwhelming."
A return to the old ITV funding formula was "not the answer to future funding of the channel, Thompson said, adding that Channel 4 remained committed to backing 4Ventures and was cutting its cost base by a third to fund an additional £30 million investment in programming.
Thompson hit out at the mediocrity of UK programming describing it as "dull and mechanical and samey". Addressing a "creative deficit in TV, Thompson argued that "when you're looking for ambitious, complex and above all modern TV, you'll find yourself watching not British, but American pieces: Six Feet Under, say, or 24".
He also criticised the Communications Bill for its "lack of specific measures to strengthen Channel 4's position".