The entry-level 13in, £999 model now comes with a 2.4GHz dual-core Intel Core i5 processor based on the Sandy Bridge architecture and a 500GB hard drive, up from a 2.3GHz dual-core Intel Core i5 processor and a 320GB hard disk.

The £1,299 13in model has a 2.8GHz i7 processor, up from a 2.7GHz model and sees its hard disk boosted from 500GB to 750GB.

The £1,549 and £1,849 15in models now have 2.2GHz and 2.4GHz quad-core i7 processors respectively, up from 2GHz and 2.2GHz Core i7 chips.

The 256MB AMD Radeon HD 6490M discrete graphics processor in the £1,549 model has been replaced by a 512MB AMD Radeon HD 6750M. The £1,849 model now has a 1GB AMD Radeon HD 6770M instead of a 1GB AMD Radeon HD 6750M. Hard disk sizes remain the same for both 15in models.

The 17in model now has the same specification as the £1,849 15in model and retains its price tag of £2,099.