We've been sent a tip-off (incidentally by the same person that let us know about Three's pricing, which turned out to be true) of a document that will be sent out today on Thursday to T-Mobile customers who've registered an interest.
According to the prices in the document, a £25 a month contract means the 16GB iPhone 4 will cost you £259 while the 32GB will set you back £349. Within that package you will get 100 minutes, 100 texts, 500MB of data and access to the company's Flexible Booster offering.
A £35 package will give you 600 minutes, 500 texts, 500MB of data, Flexible Booster, and see you pay £189 for a 16GB iPhone 4 and £269 for the 32GB iPhone 4.
The price slowly creeps up in £5 increments right up to £60 a month. For that price you will get unlimited minutes, 500 texts, 1GB of data and Flexible Booster. However, while that guarantees you a free 16GB iPhone 4, you will still have to pay £99 for the 32GB model.
The prices, if true, are a long way off three's offering of 900 minutes, 5000 texts, 5000 minutes to other Three users and 1GB of data for £35 a month; even if you factor in that you would have to pay £99 for a 16GB one and £189 for a 32GB.
On Three you can get a 16GB iPhone 4 for nowt on a £45 a month plan - the cheapest way we've seen to get one for nothing so far.
However the top end plan does beat Orange's deal. It is offering the 16GB version for free if you take up the £75 a month contract for 2 years.
Where you'd have to pay £229 for the 16GB iPhone 4, or £319 for the 32GB one on an 18-month deal at £35 a month on Orange, you can get these handsets for £169 and £269 respectively for the same monthly outlay on Vodafone. You will get slightly less minutes of calls though.
We are awaiting confirmation from T-Mobile.
We will keep you posted.
UPDATE: This is now official http://www.t-mobile.co.uk/shop/coming-soon/iphone4/ and the contract is 24 months