Apple has retracted an offer it made last week involving SuperDrive upgrades on 14-inch iBooks for just £40.

Apple has now altered this offer on the Apple Store, meaning customers will have to part with £120 (including VAT) to include a SuperDrive in new iBooks.

The company has not confirmed whether the initial offer of £40 was an error. The US site is offering the SuperDrive upgrade for $200, £112 (excluding tax) at today's exchange rate.

Apple upgraded its 12.1-inch and a 14.1-inch iBook to 1GHz, and introduced a 14.1-inch model with a 1.25 GHz processor on Monday.