Formula 1 is exploring a bold move to introduce 'green' normally-aspirated V10 engines sooner than might ever have been expected.

The sport is slated to end its 2014-2025 'hybrid power unit' era next year, ushering in heavier, more electrified turbo V6 engines.

Yet Auto Motor und Sport reports that a "contingency plan for the future" has been simmering for weeks, fuelled by the allure of loud, lightweight, fan-friendly V10s running on 100 per cent sustainable fuel.

Correspondent Michael Schmidt revealed one proposal is to delay the 2026 engines—currently under intense development—for two years, paving the way for the 'green' V10s in 2028.

"Even at an advanced stage of development, some teams are reporting that the 2026 regulations were too ambitious," he said.

Teams are said to be citing "safety concerns" over potential crashes caused by cars running at reduced speeds to recover energy, with Schmidt adding: "Many are also concerned that the show could suffer."

A "V10 working group" has reportedly been formed to explore the idea.

"The manufacturers who are putting the most pressure on the teams to do this are those who already know they're behind with their 2026 engine," an unnamed source claimed.

Red Bull and Ferrari are said to back the V10 shift, while Honda, Audi, and Mercedes resist postponing the 2026 engines by two years.

"We simply don't have enough current engines," Mercedes team boss Toto Wolff argued.

An alternative being floated is to let the 2026 changes roll out but cap them at three years instead of five, with the V10s to follow thereafter. body check tags ::