Warren East will step down as CEO of UK chip design phenomenon ARM Holdings later this year, the company announced today.

East, who is 51, has been CEO of ARM since 2001, when the London-listed company's annual sales were £146 million. Not long after his appointment, as ARM issued a shock profit warning, East said "the semiconductor industry is experiencing it worst ever downturn".

In the intervening years, chips based on ARM's design have become ubiquitous in smartphones and other mobile devices, and in 2012 group sales were £577 million.  

“It has been a privilege to lead ARM during such a momentous and exciting time for our industry and I am proud of what the ARM team of employees and partners has achieved together while I have been CEO," East said in a statement.  "ARM is a great company with a strong market position and a unique culture."

"We take a very long?term view about our business, and we believe that now is the right time to bring in new leadership, to execute on the next phase of growth and to plan even further into the future."

He will be replaced by Simon Segars, the company's president. "I have worked with Simon in the senior leadership team for many years and we share a global perspective and belief in the ARM approach to partnership and collaboration," said East of the appointment. "He is an excellent choice to lead ARM.

ARM's shares have fallen 2% so far since the announcement.

Since the acquisition of Autonomy by Hewlett-Packard, ARM Holdings has taken over the mantle of standard bearer for the UK IT industry in general, and the Cambridge cluster in particular.

It employs 2,400 people worldwide, including 1,000 in the UK.

Warren East's salary was £1.7 million. Before joining ARM in 1998 he worked for US chipmaker Texas Instruments.