While pre-orders of the iPhone 5c are now underway, many Apple fans are wondering why they can't pre-order the iPhone 5s. 

Apple has just issued emails to interested customers suggesting that the iPhone 5s will be available for order from 12.01am British summer time on 20 September.

Alternatively you can queue up outside an Apple Store and hopefully be one of the first to buy one in person at 8am on 20 September.

We wonder why anyone would pre-order at 12am when they could just join a queue the following morning and get one on the 20 September. We imagine that these orders would arrive some days later.

However, pre-ordering that night and then going and joining a queue could guard against stock shortages. It would be possible to cancel the order after purchasing the phone you want that day. 

Apple is already allowing pre-orders of the iPhone 5c. We have advice for how to pre-order the iPhone 5c here.

We also have details of the pricing for the iPhone 5c and iPhone 5s on tariffs in these articles:

iPhone 5c pricing and tariffs: how much does Apple's iPhone 5c cost on UK contract? UPDATED with Vodafone data

iPhone 5s tariffs and pricing: how much does Apple's iPhone 5s cost on UK contract?

As for why the iPhone 5s isn't available for pre-order, it's certainly curious. Perhaps the answer is actually more of a question of why the iPhone 5c is available for pre-order.

With the iPhone 5c available in multiple colour options, it is possible that Apple is gauging interest in the colours, in an effort to meet demand for customer preferences.  

Another reason why the iPhone 5s may not be available for pre-order could be supply constraints.