ARM shares closed up 29 at 366.8p to lead the FTSE 100 index on Tuesday, an all time high for the Cambridge-based microchip designer. Currently, ARM has a market value of £4.83 billion.

ARM has long been rumoured as a take over target for Apple, as the company makes the A4 chip found in the iPad and iPhone 4.

Speculation of a takeover increased this week as Intel acquired the wireless semiconductor business of Germany's Infineon for £911 million. Intel are also thought to be interested in buying ARM, although chief executive Warren East has dismissed the rumours, insisting Apple and Intel do not need to buy ARM in order to use its designs.

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