An innovative rear suspension on McLaren’s new Formula One car, first seen in testing this week, has intrigued rivals amid talk of the team having a potential ‘secret weapon’.

“I haven’t seen it in the flesh but I’d like to see a bit more of it because it does look interesting,” Ferrari technical director James Allison told reporters after McLaren’s Jenson Button topped the second day timesheets.

“But I’ve just seen some blurry pic-tures on websites at the moment.”

Photographs of the MP4-29 car showed aerodynamically-profiled ‘blockers’ seemingly shrouding the rear suspension.

Former Formula One designer Gary Anderson, writing a technical analysis on the Autosport website, said the concept should give more downforce at low speed and also reduce drag at high speed and appeared perfectly legal.

“This makes it a double whammy, giving you more downforce under braking and in slower corners and less drag at high speed,” he wrote.

“This could be McLaren’s secret weapon because, if it does work, it is not something that can be copied in five minutes as itis dependent on a number of design parameters at the rear of the car.”

Formula One is going through major change this year, with a new V6 turbo power unit and complex energy recovery systems.

At the same time, changes have been introduced that limit aerodynamic downforce with lower noses and smaller rear wings and tighter controls on exhaust exits.

McLaren had a miserable 2013 season, failing to secure a podium finish and ending up fifth overall in the constructors’ championship.

Since then, former principal Ron Dennis has regained overall control and is carrying out a restructuring of senior management with former Lotus principal Eric Boullier recruited as racing director.

Button is partnered this year by Danish hotshot Kevin Magnussen, son of former racer Jan, who won the Formula Renault 3.5 series last year.