It will come as no big surprise if Jay Leno passes David Letterman in the late-night ratings sometime soon.

Which would be quite an accomplishment for Leno and his "Tonight Show," which has never beaten Letterman and his "Late Show" in a full week of competition since Letterman went to CBS in August 1992.But not quite as big an accomplishment as the folks at NBC would have us believe.

If you listen to the hype coming out of the Peacock network, you'd think that Leno is coming on like gangbusters, rising up mightily to challenge Letterman.

But that just isn't true.

Leno's household ratings are up a slim 2 percent over last year. That's right, 2 percent.

Hardly a huge shift. And hardly an indication that American viewers have suddenly become greatly more enamored of Leno.

The race between Leno and Letterman is tight. In households, Letterman's lead is down to tenths of a rating point in recent weeks.

But that narrowing gap - Letterman used to lead by more than a full rating point - is not because "The Tonight Show" has risen, it's because the "Late Show" has fallen.

Letterman's ratings are down 16 percent from last year at this time. Which accounts for almost all of the gap that has been closed between his show and Leno's.

(Both actually finished behind ABC's "Nightline" recently, but that tends to happen when there's a big news event - in this case the Oklahoma City bombing. In an average week, "Nightline" continues to finish second or third, and its demographics are weaker still.)

Some are questioning whether Letterman's act is growing stale - whether his appeal is waning. Others point to his less-than-great performance as host of the Academy Awards, which certainly didn't help.

But the biggest reason for Letterman's decline is beyond his control. The network that he's on has collapsed in prime time.

CBS is no longer delivering much of an audience as a lead-in to Letterman. On some nights, Letterman's lead-in is 40 percent smaller than Leno's.

Which makes the fact that Letterman is still ahead - even slightly - quite an accomplishment in and of itself. And Letterman's demographics still outdistance Leno's.

On the other hand, NBC is providing a much larger lead-in to Leno than it did a year ago - making Leno's 2 percent increase look rather paltry.

So much of these so-called rating wars is based on perception. For example, ABC recently won the 30-week regular season in prime time, but the reality is that the network's ratings were actually lower than they were a year ago, when ABC finished second.

By the same token, if Letterman had come out of the gate and performed at exactly the same level he is now, he still would have been hailed as the conquering hero of late night. NBC had - and still has - all the advantages in the time period, including all that "Tonight Show" history and a much stronger affiliate lineup.

In all probability, the Letterman-Leno battle will be closely competitive for the foreseeable future. Which may not be a bad thing for either show.

LETTERMAN IN LONDON: Letterman's ratings seem certain to rise the week of May 15, when he takes the entire "Late Show" gang - and his mother - to London.

That's right. Not only will Dave be doing the show from Great Britain, but he'll be taking his mom, Dorothy, along as a special correspondent, reporting from various historic locales around England. Dave's mom, of course, became an international celebrity while reporting from the 1994 Winter Olympics for the "Late Show."

Dave will also be taking Mujibur and Sirajul along, and will present an edition of Stupid British Pet Tricks. His guests will include Elton John, Pierce Brosnan, Jennifer Saudners and Joanna Lumley of the hit British sitcom "Absolutely Fabulous," Elvis Costello, Peter O'Toole and Annie Lennox.

Can't wait.

LATER LATE-NIGHT BATTLE: It's possible that Conan O'Brien and Tom Snyder will go head-to-head locally this fall, but not at the hour they're supposed to.

KUTV-Ch. 2, which is being purchased by a CBS/Group W joint venture and is tentatively scheduled to begin airing CBS programming at midnight on July 1, will - of course - air Letterman weeknights at 10:35 p.m.

But instead of "The Late Late Show with Tom Snyder," Ch. 2 will air the syndicated talk show "Carnie" at 11:35 p.m. Snyder will follow at 12:35 p.m.

(Which comes as more than a bit of a surprise.)

Future NBC affiliate Ch. 5, meanwhile, plans to air "The Tonight Show" at 10:35 p.m. And at least one episode of "M.A.S.H." at 11:35 p.m., followed by "Late Night with Conan O'Brien."

But if Ch. 5 decides to begin a 5 p.m. newscast in the fall, KSL will air a second episode of "M.A.S.H." at 12:05 a.m., pushing Conan back to 12:35 a.m. - opposite Snyder.

MENDING FENCES: Jay Leno and Dennis Miller have kissed and made up.

After a bitter feud lasting years, the two comedians/talk show hosts have finally buried the hatchet.

The problems began three years ago when Leno succeeded Johnny Carson as host of "The Tonight Show" and Miller started his own syndicated late-night talk show. Leno's pit bull producer, Helen Kushnik - who has since been fired - warned potential guests that they couldn't appear with Jay if they did Dennis' show.

"Dennis Miller" didn't last long, and when it was canceled he loudly and bitterly denounced Leno and the booking tactics employed by Kushnik. The two former friends hadn't spoken since.

But, apparently, Miller called Leno last week and each apologized to the other. Now Leno is going to appear on Miller's HBO show tonight, and Miller will appear on "Tonight" on Wednesday.

Aren't happy endings great?

BIG IMPROVEMENT: Jay Leno still can't do a decent interview, and he continues to rip off Letterman's style night after night.

But one thing about his "Tonight Show" has changed for the better - the band leader.

Branford Marsalis may be a wonderful musician, but he was a terrible late-night talk show band leader. They guy had no discernible personality on the air and looked uncomfortable and/or just plain awful during comedy bits.

(And, while Marsalis' departure from the show was billed as amicable, rumors persist that he was encouraged to take a hike by various powers that be at the network and within the show.)

His replacement, Kevin Eubanks, is a big improvement. He's fun and personable, and makes his boss look better.

Leno can't ask for more.