It was, Virginia Sen. Charles J. Colgan claimed immodestly, "the kind of bill people would hate to vote against."

Armed with horror stores about bank errors, the Prince William County Democrat sponsored legislation this year that would make banks pay a penalty for their mistakes just the same as the fees that banks charge to their customers for overdrafts.

The idea caught on in the Senate, whose members passed it last week, 34 to 0. Today, what one legislator dubbed "probably the best bill of the session," was effectively scuttled in a House committee after running afoul of Virginia's powerful banking lobby.

"They're all around us," whispered Colgan as he sat in the House Corporations, Insurance and Banking Committee meeting and surveyed a roomful of representatives from the banking and savings and loan industry.

Though not a single bank lobbyist actually bothered to testify against the bill this morning, Colgan said afterward that it was obvious that the bankers had got to the committee.

"I saw them talking to the members in the hall," he said."They've been planning to kill it on the House side all along."

The death of Colgan's bill was another testimony to the banking industry's clout in a conservative-minded Assembly that has already approved several measures that would raise the interest rate on the money Virginians borrow.

At least a dozen leading industry sponsored bills recently sailed through the legislature and are awaiting Gov. John N. Dalton's signature. The measures would mean progressively higher mortgage rates and are designed to help state lending institutions stay competitive with federally chartered banks and savings and loan firms in a period of soaring inflation and interest rates.

One of the bills, for example, would allow savings and loan associations to issue home mortgages with rates that would climb -- or drop -- as interest rates vary.

Colgan, concerned that lawmakers this session "haven't given the little guy anything," had urged approval of his bank bill on the theory of "what's good for the goose if good for the gander."

If a bank can charge its customers for their overdraft mistakes, he argued, the customers should collect the same fee if their checks bounce because of a banking error.

"I don't know about your area, but in my area it can cost $9 or $10 every time a check bounces," Colgan told the committee. "The banks just go right into your account and deduct that amount."

The Prince William County senator described the case of one of his constituents whose account was overdrawn because of a banking error. "He bounced 17 checks, and the bank fine him $153," Colgan said.

When the customer discovered the bank's error, Colgan said, he asked the bank to pay him $153. The bank refused.

"If the banks make an error, it causes you a lot of trouble and sometimes you have to take off work to go down and straighten it all out," Colgan said.

The House committee members, many of whom are directors or presidents of banks or lending institutions or who represent clients with banking interests, openly were skeptical about the measure.

One lawmaker, grinning, labeled it a "'summer bill," legislative slang for measures aimed at helping consumers. Another worried aloud that the bill could only apply to Virginia's 160 state-chartere banks, leaving its 72 banks in the state chartered by the federal government unaffected. A third committee member suggested that instead of paying the fine the bank could write a letter of apology to the customer.

"That's fine, but in that case why not let the customers write a letter of apology when they make mistakes?" Colgan asked.

Although Del. Alexander B. McMurtrie Jr. (D-Chesterfield), the chairman of the subcommittee that will review Colgan's proposal next year, said he believed the issue "ought to be looked into," banking spokesmen didn't agree.

"I don't think this bill is necessary," said W. O. Pearce, executive vice president of the Virginia Bankers Association. "I've handled customer relations since 1971, and I can't recall of one time when an error was the bank's fault."

Pearce complained in an interview that banking horror stories "never give the bank's side of the story," and said that "99.9 percent of the errors are the customer's errors."

Colgan's bill was in effect killed, carried over to the 1981 session after he offered to amend the measure into little more than a request that banks pay for their mistakes. The senator said afterward that if banking errors are so rare, "then why are they against the bill?"

Del. George H. Heilig Jr. (D-Norfolk), who sponsored the bulk of this session's banking measures, said Colgan's bill was not the right way to address the problem.

Heilig, who said he is not financially connected to any banking institutions, said that his bills were intended to help Virginia's banks "maintain competitiveness" with federally chartered institutions that can charge higher interest rates on the money they lend.

He said that the measures also will help consumers because they will keep mortgage money available. "I happen to believe that people want to borrow at a high cost if it's a choice between that and no money at all," Heilig said.