The handset is the first Apple product to go on sale in the UK since the death of Steve Jobs, the former chief executive of the firm.
When doors opened at the Apple store in Covent Garden in London, hundreds of consumers flooded through the doors to pick up the handset.
Described by Apple has the "best iPhone ever", the new handset is the most popular product in the firm's history in pre-order sales, reaching one million in a single day.
Meanwhile, Apple is currently engaged in an argument over its use of patents with Samsung, which has declared its intention to block the sale of the new iPhone 4S in France and Italy.
The South Korean firm said that Apple has used its 3G wireless technology without paying for it.
