Andy Wilman has told how BBC management were unsure whether they wanted to keep Hammond after he made his first series in the Top Gear reboot
Wilman quit the long-running TV series in the wake of Jeremy Clarkson's departure and the BBC plans to relaunch Top Gear with new presenters.
But the TV executive, who alongside Clarkson, Hammond and James May, are believed to be negotiating with a streaming service like Netflix or Amazon, said of the show: "I don't think we'll see the like of it ever again."
Writing about the success of the show in the latest edition of Top Gear magazine, Wilman said: "The show that finally ground to a halt just over a month ago was a colossus."
He added: "In our heads we were making a car show for car dweebs, but as series four went to five went to six, we realised that the actual growing was sprouting in directions we hadn't reckoned on.
"Because we never planned it, I don't think we'll see the like of it ever again."
He told how BBC management were unsure whether they wanted to keep Hammond after he made his first series in the Top Gear reboot.
"For a while, for some reason I cannot fathom, the BBC management had a wobble about Richard and in their usual, classic HR style said to him, 'We may not want you back for the second series, but, anyway, have a good Christmas'."
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He said that on one occasion they "told us that market research showed our show was attracting young, lifestyle, trendy viewers to BBC2, so perhaps we should think about getting a young, lifestyle, trendy presenter".
"Ever keen to assist, we searched high and low and eventually came up with just the man: James May."
He added: "At one point, the Meddling Department arrived bearing more news from the outside world. Nearly half of our audience, they now declared, was female.
"Before they had a chance to follow that up with the inevitable suggestion to get a woman presenter, we shooed them out and carried on."