Aston Martin had to move away from Mercedes in order to target the world championship, according to Group CEO Martin Whitmarsh.
Honda on Wednesday announced in Japan that it will team up with Aston Martin in 2026 for the all-new engine regulations.
Whitmarsh has vast experience of working with both Mercedes and Honda from his time at McLaren, and he says the new works deal is Aston Martin's path to victory.
"Mercedes has been and continues to be a great partner," he said.
"They want to win, we are here to win too - and that's where there is some incompatibility in these two missions, so we made this decision.
"If you want to be number 1, you have to beat Mercedes too, and beating such a strong organisation is extremely difficult when you depend on them for intellectual property, equipment and components," Whitmarsh continued.
He said Aston Martin's ambition, which has began to crystallise this year with a string of early podiums in 2023, has changed starkly in the recent past.
"We've been able to achieve good results with a modest budget, but now the situation has changed," said Whitmarsh. "We want to win, and the 2026 regulations require not only the full physical integration of components and parts, but also at the operational level.
"It is impossible to win without this full working cooperation, which is why we have made this decision and are delighted to have such a fantastic partner as Honda."
