John Gardner wrote a best-selling spy novel in England some 20 years ago titled ''The Liquidator,'' and he has written 22 novels since, including ''The Nostradamus Traitor,'' ''The Werewolf Trace'' and ''The Dancing Dodo.'' Mr. Gardner made the best-seller list in this country for the first time two weeks ago, and if his name is still not familiar to American readers - except to those who might confuse him with the American writer of the same name - the hero of his ''License Renewed'' bears a name that is indeed well-known: James Bond. Yes, James Bond, 007, that bold, urbane creation of the late Ian Fleming. Fourteen years have elapsed since the last Bond book, and although the world's most famous spy has not aged a day in that time, the James Bond of the 1980's drinks moderately, smokes low-tar cigarettes and drives a fuel-efficient Saab 900 Turbo instead of a Bentley. (Bond only drove Aston Martins in the movies.)
If the new James Bond sounds very much unlike his former self, readers appear to have few objections. Even in Bond's British homeland, Mr. Gardner said in a recent telephone interview, ''The book and I have been welcomed with open arms by the great aficionados of Bond. The reviews have been very kind so far and so have the interviewers. The people who own the literary copyright knew Fleming well and they all worked with him.''
Perhaps one reason Bond fans do not object to the new 007 is that, although the changing times have dulled many of his male chauvinist edges, Bond remains very much a charmer, as Miss Moneypenny would still attest. And even though Bond's pipe-smoking chief, M, is in the process of withdrawing the Double-O status, which conveyed license to kill in the line of duty, changing circumstances soon dictate a renewal of that license.
The owner of the Fleming copyright is Gildrose Publications, Ltd., whose board of directors chose Mr. Gardner to write the Bond books. Gildrose is a subsidiary of Booker and McConnell, which according to Mr. Gardner is a large London-based conglomerate ''to which Mr. Fleming sold his copyright long before he passed away in order to have a regular salary.'' The new book, incidentally, is dedicated to the memory of Ian Fleming.
''Apparently Gildrose had a list of six candidates and I was at the top,'' he said. ''I supplied them with four possible narrative outlines, they picked one of them and asked me to do certain things. What they wanted was for me to think in terms of Bond having been on ice for a while, but being quite up to date about what's been going on in the world during the past two decades.''
In the book's acknowledgments, Mr. Gardner explains that all the ''hardware'' used by Mr. Bond in the story is genuine: ''Everything provided by Q Branch and carried by Bond - even the modifications to Mr. Bond's Saab - is obtainable on either the open, or clandestine, markets.'' That means trouble for Franco, the international terrorist, and the Laird of Murcaldy, the renowned nuclear physicist, when Bond sets out to make the world safe from accidental nuclear holocaust.
Mr. Gardner, 54, was born and raised in England. His father was an Anglican priest, and he himself was ordained as a clergyman, although he soon became a theater and film critic for various British newspapers. These days he lives in Dublin, and his contract calls for him to write at least two more Bond books.
Before he agreed to take up the Fleming mantle, Mr. Gardner said he worried whether it would pose scheduling conflicts, since he had already contracted for several books of his own during the next few years. He intends to honor both contracts. ''Now I don't think it will be much of a problem,'' he said, ''because I'm used to writing all the time anyhow.''