Speaking at today's Media Summit on the subject of how to preserve his organisation's ability to make great public service television, Johnson reiterated Channel 4's preference for reaching an agreement with BBC Worldwide.
Without mentioning Five and ITV, which have put themselves forward to merge with C4, Johnson outlined his resistance to rolling Channel 4 together with a commercial broadcaster.
"I worry that profit seeking shareholders would sign up to all sorts of PSB commitments as a price of gaining a stake in Channel 4 -- and then lobby to remove them.
"I also fear that part privatisation by stealth of Channel 4 would mean there could only ever be one buyer for the rest -- at a discount -- and that taxpayer value would therefore be destroyed.
"My view is that if the political desire is there to sell off Channel 4, then do a proper auction and maximise proceeds.
"I happen to think, after extensive discussions with politicians on all sides, that there is currently no appetite to privatise Channel 4 at Westminster.
"But if our political masters decide to do that, don't fudge it with a messy deal that neither secures PSB output nor the highest price for the taxpayer."
Johnson's comments follow news yesterday that ITV has discussed plans for a three-way merger with Channel 4 and Five with the Government.