The Maryland House of Delegates, ending a week of acrimonious debate, gave final approval tonight to legislation that would allow banks and retailers to raise the interest rates on most consumer loans from 18 percent to 24 percent.

The 80-to-48 vote, a wider margin than the debate would have indicated, represents the most significant legislative victory for the lending industry here in years. Although leaders of the banking lobby hailed the victory, they were mindful that the bill still must be approved by the Senate within the remaining two weeks of the legislative session.

The months of controversy that preceded tonight's vote centered on whether banks and retailers need higher interest rate ceilings to make more credit available to consumers. Among those who came to accept that view were Gov. Harry Hughes and Attorney General Stephen H. Sachs, both of whom reversed their earlier opposition to interest-rate deregulation.

Supporters of the bill argued that small loan companies, in particular, need the option of charging higher interest on consumer loans to avoid going out of business.

Tonight's action took some of the steam out of vocal anti-bank sentiment that was reflected in last week's House vote to prohibit issuers of credit cards from charging membership fees. Supporters of the legislation said they were responding to the action of the state's four biggest banks, which already have decided to move their credit card operations to Delaware so that they can charge membership fees.

Critics of the bill, led by Del. Steven V. Sklar (D-Baltimore), who has become the chief nemesis of the banking lobby, argued that it was not designed to aid the consumer or the small loan companies, but was merely the work of a powerful banking lobby intent on winning higher finance charges on credit cards.

"This is a legislative wrap-up bill," Sklar said during an impassioned speech on the floor tonight. "The banks wrote this bill, and then wrapped themselves up in the small loan companies, the retail stores, the furniture dealers, and the retailers, because they couldn't get a banking bill by themselves. If they could have made it on the merits they would have had a separate bill called 'bank credit cards.' "

Sklar and his allies challenged assumptions that banks would move their operations to Delaware if the bill failed.

"People tell us we're driving the banks to Delaware," Sklar said. "That's not true. They are moving to Delaware because the Maryland legislative process is too damn inconvenient for business. My feeling is, let 'em go. There will still be good banks here, and banks offering credit cards."

One bank, Bethesda-based Suburban, announced after last week's vote against credit card fees that it would join the other three banks in moving out of the state.

"At no point did we hear from consumer groups saying we need this bill," said outspoken Del. Andrew Burns (D-Baltimore). "This is a yo-yo bill. It was an up-and-down scale of interest rates for only one reason-- the rate was changed to wherever the votes were to get the bill passed."