Visions of sugar plums can dance in our heads for just so long. Pretty soon it's time for them to scram.

Television is so saturated now with holiday special that it may be pushing our tolerance for glad tidings to the bursting point - fostering Ebenezer Scrooges rather than jolly old elves.

And the networks have a hefty backlog now of specials that run year after year after year, turning into pure profit for them, but at the risk of making wearied deja viewers of us. "How the Grinch Stole Christmas" is a beautifully produced cartoon, but during its 10th rerun on CBS this year it may have occured to some people to start rooting for the Grinch.

The honor of the holiday special is somewhat redeemed tonight by "Perry Como's Olde English Christmas" on ABC (Channel 7, 10 o'clock). Taped and filmed around London, it's an attractive package that neither grates nor cloys.

In that it is decidedly a typical. Most of the network Christmas specials try to pass off innocuousness as wholesomeness and inanity as innocousness. Singer John Davidson did an English-themed holiday special himself last week on ABC, but this one was firmly rooted in the soil of Hollywood add up to here in members of Davidsons uninteresting family. Some of them were even less interesting than he was.

Up against such competition as the MacDavis Christmas special on NBC or the Carpenters Christmas special earlier on ABC, davidson may not have looked all that bad. But Como shows how it should be done; how one can glide softly through an hour of TV without becoming the host at a slumber party.

Como, after all, is the original beige eminence. One of the secrets of his TV longevity is his professional ability to convey an amateur's delight at being on television, even after 25 years of it. This is a very tricky feat, and it's part of what separates Como from the clones.

His program also features Petula Clark, who should have become a much bigger musical star than she did, and Leo ("When I Need You") Sayer, who has a funny, impish body and an oversized Harpo haircut. His big number would be much more watchable if he were not mobbed by a flock of infernal, hyper-active, bumtwitching TV dancers. Producers still make the mistake of thinking they have filled the screen when they only have crowded it.

Como sings his annual "Ave Maria" finale from St. Paul's Cathederal and takes a brief shopping spree at Harrod's. Except for the incongruous babble of canned laughter during the opening scene, this is a patently pleasing and unobjectionable Christmas show.

And it's new this year. Many of the Christmas specials being aired by the networks are not. "A Charlie Brown Christmas" had its 18th outing on CBS earlier this week. "Frosty the Snowman" romped on the same network for the 10th time.

ABC is showing "The Year Without a Santa Claus" and CBS is airing "The House Without a Christmas Tree" for the fourth time each.

"John Denver's Rocky Mountain Christmas" will show up on ABC Dec. 23 for the third time and ABC's "Santa Claus Is Coming to Town" is coming to town for the eighth time.

This is not an embarrassment of riches. It is a case of maximizing profits at a very high-profit time of year. Many of these shows barely deserved one airing. While it's ture that there are new children in the audience each year, it's also ture that the networks could easily give some of the perennials a rest now and then and stimulate more new production that would at least provide a variety of choices.

If the brakes aren't put on and the blitz continues, we all run the risk of arriving at the holidays already Christmassed out. Nothing depresses like excess.