The head of Intel’s ultra mobile products has been forced to apologise after one of his subordinates slammed the iPhone’s performance and laid into rival chip shop ARM.

At Intel’s Developer Forum, which took place in Taiwan last week, Shane Wall, vice president of the chip giant’s mobility group, was reported to have said that the iPhone “struggles” to run any application that, “requires any horsepower at all”.

However, Wall also took a pop at ARM, saying that ARM’s chips were responsible for the Apple device’s shortcomings.

As Apple is a big customer of Intel for desktop and laptop chips, this obviously isn’t good PR. So, Anand Chandrasekher, general manager of the group responsible for Intel’s ultra mobility products, issued a grovelling correction on the comments.

Chandrasekher went so far as to acknowledge that Intel’s own mobile chip, the low power Atom processor, “Does not yet match the battery life characteristics of the ARM processor in a phone form factor; and, that while Intel does have plans on the books to get us to be competitive in the ultra low power domain – we are not there as yet.”

Course, there’s probably no love lost between Intel and ARM. It wasn’t so long ago that analysts predicted that Intel is to take a good kicking in the ultra mobile space, largely at the hands of er, ARM.

In the summer, Strategy Analytics predicted that global sales of MIDs (Mobile Internet Devices) will reach 1 million units in 2008, and will continue to grow at an average annual rate of 102 per cent to reach 69 million units by 2014.

However, Intel-based gadgets are expected to take a back seat to those powered by mobile industry heavyweight ARM.

“Intel’s Moorestown system-on-a-chip will be critical to the company’s MID strategy,” said Peter King, director of the Connected Home Devices unit at Strategy Analytics. “But until this arrives in 2009 or 2010, ARM-based vendors will use this window of opportunity to establish market leadership positions.”

Ultimately, the proven advantages of the ARM ecosystem in mobile devices are seen as outweighing those of the Intel platform, leading to ARM devices comprising the majority of MID sales by 2014.