Internal feuding broke out in leafy Monza. Down at McLaren, where they have shown the patience of Job with engine makers Honda, fingers are finally being pointed in the direction of Japan.

For the Mail on Sunday has learned that McLaren are so exasperated at Honda's woeful performance that they have written to the company's president, Takahiro Hachigo, calling on him to replace the head of their F1 division, Yasuhisa Arai.

Little wonder. Honda's engine is both unreliable and underpowered. The litany of problems continued on Saturday in qualifying for the Italian Grand Prix, with Jenson Button and Fernando Alonso 16th and 17th fastest — more than four-and-a-half seconds behind pole-sitter Lewis Hamilton.

On Saturday, Spaniard Fernando Alonso was just 17th fastest in qualifying for the Italian Grand Prix

Jenson Button, in 16th, was more than four-and-a-half seconds behind fellow Brit, pole-sitter Lewis Hamilton

Both McLaren drivers will take grid penalties on Sunday for using their ninth internal combustion engine in 12 races. The permitted number of engines for the season is five.

All this recurrent embarrassment comes despite Arai repeatedly making outlandish predictions about improved performance. Prior to this weekend, he claimed, risibly, that McLaren's brake horsepower would be 25 per cent greater than Renault's. In fact, McLaren, as Alonso said, were losing three seconds on the straights.

Sitting at McLaren's regular post-qualifying press conference, Arai was lost for answers. He evaded questions and giggled. Such responses as he did provide suggested that communication with his English team-mates might be somewhat less fluent than is helpful.

He was asked if he would consider resigning from the job for which he is paid £550,000 to make way for someone else. He declined.

While the others sharing the stage with him — Alonso, Button and McLaren's racing engineer Eric Boullier — were reluctant to take a pop in public at Arai, several of their responses contained coded barbs. For example, Boullier said: 'As one team, I have to agree with Arai San's statement.' Asked if the right men were in the right jobs at Honda, he could muster no more than: 'I guess so.' Translated, that means: 'No way.'

Behind the scenes, McLaren offered to poach staff from Mercedes to help Honda understand the engines, which are fiendishly complex. Honda, a proud company to whom loss of face means so much, said no thanks.

McLaren's racing engineer Eric Boullier has been reluctant to take a pop in public at Yasuhisa Arai

McLaren are expected to lose two major sponsors, Johnnie Walker and Santander, at the end of the year, costing them £20million annually. This mess hardly helps their finances. 'The McLaren brand has not been damaged yet as there is such a strong record over many, many years,' said Boullier. 'But if we cannot finish where we finished last year, there will be a direct loss of revenue because the business is driven by sport.'

Further along the paddock, there were rumblings at Mercedes between Nico Rosberg, who only qualified fourth, behind team-mate Hamilton and the Ferraris of Kimi Raikkonen and Sebastian Vettel. Rosberg blamed the fact he used his old Spa engine for a lack of grunt.

'We had to go back to an engine that has done six races and every kilometre you lose a bit of power,' he said.