After weeks of backroom negotiations, a Virginia legislative committee today approved a reapportionment plan that would protect most of the state's 100 delegates, but which many legislators feared would be rejected by the courts.

What worried many General Assembly members was that the plan's House districts would vary in size well beyond the limits that the Supreme Court has allowed.

Late yesterday afternoon, a less serious but more embarrassing defect also surfaced and it didn't take a judge to discover the error.

Hours after the plan was reported to the full House, members of the Privileges and Elections Committee were redfaced when they discovered their proposal would create 101 House districts -- one more than the state Constitution allows.

"I guess you could say it's a little bit of a setback," said committee Chairman John D. Gray, as he hunched over maps and census figures late this afternoon, attempting to find another solution. "We've gone back to the drawing board," he said.

The snafu may force the assembly to stretch its already-extended special reapportionment session to midweek. In the state Senate, another elections committee approved a reapportionment plan for its 40 members that is likely to encounter strong opposition from a coalition of dissident Democrats and Republicans.

The 101-member House plan was the product of a series of private meetings that culminated in a secret committee session this morning. It was a plan that appeared to have something for everyone -- a fact reflected in the panel's 18-to-1 vote to send it to the full chamber.

But the plan also contained legislative districts with populations that vary by as much as 25 percent from the ideal size, leaving the entire House reapportionment vulnerable to court challenge. "If you come out with such deviations as that, it won't [survive a court challenge] -- that's for sure," said House Speaker A.L. Philpott, before he knew of the plan's other defect. "I don't know what the heck I can do. I surely can't draw a plan."

In a 1971 Virginia reapportionment case, the Supreme Court held that variances in excess of 16 percent would seriously jeopardize equal representation and therefore were not acceptable.

Common Cause lobbyist Jane Moriss had argued that the plan was an invitation for a lawsuit. "They are asking for a challenge," she said, declining to predict whether her group would sue but saying that others would.

Many Northern Virginia delegates had dubbed the plan the "B.L." or "Brotherly Love" plan because it favors incumbents. But said they favored it because it granted Fairfax County the two additional delegates they had come to Richmond to win.

Others said the plan's initials stood for "Barely Legal" because of the problems it would encounter passing court review. "this plan may not even deserve to be called 'Barely Legal,'" said De. Mary Marshall (D-Arlington). "It is beyond the tolerances the courts have allowed in any case we know of. But it satisified more people than [Earlier plans], and we were primarily concerned with Northern Virginia."

The House committee approved the plan at a morning session, and it was not until some committee members sat down after lunch to put some finishing touches on it that they counted the numbers and discovered they had created 101 delegates.

While the committee's embarrassed leaders denied they had intended the plan to be sent to the House floor, other lawmakers ridiculed that claim -- and the committee as well. "I've always worried about their capacity over there," said Sen. William Truban (R-Shenandoah), who said two senior committee members had told him they had sent the bill to the floor. "Nobody counted the numbers."

The committee's decision on the plan at a closed session called by Gray, who did not poll the panel before closing the meeting to the public. Virginia's open-meeting law requires that committees take a vote before going into secret session, and also requires that the subject of the meeting be limited to matters pertaining to pending or potential litigation.

That second requirement also was apparently violated when the panel during its closed meeting went around the table for a straw vote on the plan that was later approved in open session.

After a rapid-fire series of voice votes in which a half dozen amendments were defeated, the Senate committee approved by 10 to 5 a reapportionment plan almost identical to that which the panel had passed last week. The Senate's Democratic leadership had returned that plan to the committee when it appeared they might not have the votes to win passage on the floor.

Major objections today came from Norfolk's three Democratic senators, who object to their city being split into three districts, and from the Senate's nine Republicans, who contend some of their districts are being gerrymandered. Both groups said they would try to amend the plan tomorrow.

"We won't know if we've got the votes until we get on the floor," said Fairfax Sen. Clive DuVal, chairman of the Democratic caucus and a supporter of the plan.

Opponents said they, too, were uncertain about tomorrow's vote, although one Republican, Alexandria Sen. Wiley F. Mitchell, predicted the measure would pass. "It appears Hunter Andrews made sure enough arms were twisted over the last two or three days," said Mitchell, referring to the Senate majority leader.