Jenson Button joked he spent the best part of Friday sampling desserts in the McLaren motorhome after being restricted to 15 laps on the first day of practice at Monza.

Button and McLaren arrived at Monza knowing it was in for another tough weekend at the power-dependent Italian circuit and with penalties looming for tactical engine changes. After completing 12 laps in the morning, Button had just three to his name in FP2 before McLaren asked him to return to the garage to check an "anomaly", and he did not re-emerge before the end of the session.

Asked if he had the chance to get a good impression of Pirelli's new tyre pressures, brought in after the tyre failures of Belgium, Button joked: "No, but I've done a sample of the desserts in the motorhome and I've found the chocolate brownie always wins."

Button says his FP2 issue was down to a coolant leak and admits he will now have to focus on the data collected by team-mate Fernando Alonso.

"We had a leak, coolant leak, so the car was crying. They couldn't change it in time, we tried but we couldn't change it in time. We'll learn from the other car and see what we can do.

"That's the issue, and we couldn't change it in time, so I didn't get out. Not a very good day; one lap this afternoon and only a few laps in the morning. So not very good preparation, buy hey-ho. It was going to be a difficult weekend anyway but we've just made it more difficult for ourselves."

Asked by one journalist if it was frustrating to still be having issues at this stage of the season, he replied: "No, I'm really happy about it ... Of course, you state the obvious. I think anyone would be disappointed."