A controversial British proposal that would require 25 percent of government-financed academic research to be assessed on its social and economic impact will be delayed by a year, Britain’s higher-education minister announced on Friday.

David Willetts, minister of state for universities and science, mentioned the delay in a speech at the Royal Institution, the world’s oldest independent research body. In the speech, his first address on the new government’s vision for science, Mr. Willetts said the “surprising paths which serendipity takes us down is a major reason why we need to think harder about impact.”

Thousands of academics, including several Nobel laureates, have signed a petition opposing the plan, which was announced last September. Noting that scientists have been “wary,” Mr. Willets said the delay would allow the national agencies that finance higher education “to figure out whether there is a method of assessing impact which is sound and which is acceptable to the academic community.”

Britain’s main faculty union issued a statement welcoming what it called the “reprieve” as a victory for its campaign against the proposal, which it had said would “wreck the very basis of innovation in knowledge.” It said the union would continue campaigning against the measure.