Howard County Executive Elizabeth Bobo and County Council Chairman C. Vernon Gray have joined angry parents and students in protesting the local school board's decision to eliminate summer school for virtually all students this year.

In an unusually strongly worded letter read aloud at a crowded board meeting Thursday night, Bobo and Gray described the board's action as "unneccessary" and "rash" and asked board members to restore the program before its original June 22 starting date.

"Cutting the summer school program at this late date is extremely unfair and disruptive to the students and parents. Tuitions have been paid and people have adjusted their summer's plans on the expectation of the summer school program being offered," they wrote. "We strongly feel that all of this disruption and inconvenience are, to say the least, uncalled for."

The letter -- and the public forum in which it was released -- was an unsual breach of the Howard County government's unwritten rule not to interfere in the school board's decisions.

The dispute also highlights the increasing tensions between local governments and school officials in suburban areas, where highly acclaimed, costly school systems are in growing competition for shrinking pools of funds.

In their statement, Bobo and Gray reiterated their desire for "a cooperative working relationship with the Board of Education." They added, however, "we feel it would be irresponsible for us to remain silent and stand idly by in the face of such a rash action."

Superintendent Michael E. Hickey said yesterday that he was "disappointed" by the letter, calling the officials' statements "second-guessing" and "cheap advice."

"I don't know if this sort of thing serves a useful purpose, except for a political one," he said.

The five-member board voted unanimously June 1 to eliminate summer school classes for all but about 350 incoming and graduating seniors to make up a $4.2 million reduction in the $97 million fiscal 1988 budget they requested from the county.

The board estimated that eliminating summer school for 1,000 students and 100 teachers would save $134,000.

But Bobo and Gray, pointing out that the school board's budget had been increased by nearly $10 million over this year, said the board could have made up for the reduction by cutting a less visible budget item. They mentioned in particular $412,000 the board plans to spend to purchase new photocopying equipment for each of Howard's 47 schools.

School board members Anne L. Dodd and Karen Campbell defended their choices. They said the copying machines, for instance, had been requested by school principals and supported by local PTAs.

"I'm getting as much mail and as many phone calls about {cuts in} the music program and cross-country as I am about summer school," Dodd said.

Dodd said the board would formally respond to the letter at its June 25 meeting.