Mr Leigh said: "That was somewhat ironic. In fact, we toyed with the idea of a novel on several occasions.
"The book caused a fairly substantial flap at the time, both here and in the United States. We were very careful to state that in synthesising the material, we were presenting a hypothesis.
"When I first heard about The Da Vinci Code, I ordered it. I said to my agent, 'If they make a film of this, I will be p****d off'."
He added that the writer Paul Schrader had been interested in making a film of his book for Paramount Pictures before he wrote the screenplay for the 1988 film The Last Temptation of Christ.
Mr Leigh said: "That's another reason for our grievance. In effect, Brown has ruined our material."
Intriguingly, the only mention of his book in The Da Vinci Code is when its villain, an eccentric English historian called Sir Leigh Teabing, lifts a copy off his bookshelf and says: "The authors made some dubious leaps of faith in their analysis, but their fundamental premise is sound."
The name Leigh Teabing is an anagram of Leigh and Baignent, while his physical description - he walks on crutches - is allegedly based on Mr Lincoln, who walks with a limp.
Mr Leigh said: "None of us can work out why he did that. Was it a jokey homage, or a nudge, nudge, wink, wink?"