Adrian Newey has said that he played only a "small" role in the initial development of this year's Red Bull car.

Earlier, it was rumoured the radical 2017 regulations had re-fired the famous designer's interest, but then Red Bull began the season clearly behind Ferrari and Mercedes.

"No, my involvement was small," Newey told Brazil's Globo.

"I know people think I designed the car, but it's not true. I started working on the RB13 after Australia."

Newey does acknowledge that the car's big upgrade package in Spain - a "massive" step according to Max Verstappen - is his handiwork.

"Yes, the new parts were devised following my involvement in the project," he said.

"We still have a lot of work to do, but I think we can make it faster still. How much is unclear."

Newey said that now he is deeply involved in F1 design again, he is enjoying the very different 2017 rules.

"There's a lot to be understood and better explored, and it's an interesting challenge," he said in Barcelona.

Red Bull's Daniel Ricciardo finished third at the Spanish Grand Prix, while Max Verstappen had to pull out after one lap due to a collision.