Button: Belgian GP felt 'embarrassing'

From starting 19th on the grid at Spa-Francorchamps after a host of penalties, Button finished 14th and a lap down on race-winner Lewis Hamilton's Mercedes.

"I had a problem with the recovery and deployment of the ERS pack," Button explained.

"So the moment I got to the top of Eau Rouge I had no deployment all the way down the straight, and the same with the back straight.

"I don't know why that was, we're looking into it, but for the whole race it wasn't correct.

"So when you're just running on a petrol engine there's not a lot of power there compared to other people with electric motors as well.

"It's not an issue I've had before, but the pace wasn't good anyway, as you saw with Fernando [team-mate Alonso].

"But when you haven't really got any deployment on the straights, that's a lot of power these days.

"When you don't have the electric motor, you're losing 160, 180 horsepower. I was basically just driving round and keeping it on the black stuff.

"It was a tough day, embarrassing really, driving around at the back."

Over the summer break Honda upgraded the power unit with the use of three development tokens, with motorsport boss Yasuhisa Arai suggesting the system would be close to matching the power output of Ferrari.

That proved to be far from the case, though, as McLaren found itself only ahead of perennial backmarker Manor, and some way adrift of the likes of Sauber.

Button admitted he would be happy for Honda to prioritise performance and sacrifice reliability.

"I'd rather have more effort on power," he said.

"That's the aim we have right now: more power.

"Reliability is second because we'd like to see ourselves quicker and less reliable. I wouldn't have an issue with that.

"But the performance is something that's difficult to find. Reliability's probably a little easier."

As to whether he is still enjoying F1 in languishing around at the back, an honest Button said: "A race like that, no, not at all.

"The last eight laps were quite fun watching a few guys scrapping, but apart from that, not at all.

"Loving F1? Yeah. Qualifying was awesome, I enjoyed driving the car, but not the race."