Apple is reportedly going to announce its Apple Pay service in the UK from its World Wide Developer Conference, starting tonight.

Apple is also expected to announce a UK launch date of two months time. Apple Pay is already available in the US.

Until now banks and mobile operators have failed to get a mobile contactless payment system up and running on any decent scale. Apple has been in talks with banks and retailers since last year. It is expected to bring mobile payments into the mainstream when Apple Pay launches in the UK in two months.

Apple's iPhone 6, iPhone 6 Plus and the Apple Watch will be able to tap-to-pay in shops.

The system uses the built-in NFC chip in the iPhone in conjunction with the Touch ID fingerprint reader to secure tap payments. Once unlocked the Apple Watch also can be used to tap-to-pay using its built-in NFC functionality.

Apple Pay can also be used online to make payments from within iPads and older iPhones. Since these do not have NFC they won't work for payments in real world shops.

The UK's Transport for London is already taking tap payments from US customers visiting with Apple Pay setup on their phones and watches.

A MasterCard senior executive said that the company is "absolutely ready" to support Apple Pay in the UK.

Contactless spending trebled last year to £2.3bn. With contactless payment machines in more and more retailers the UK is a welcome venue for Apple Pay.

Check back from 6pm tonight to hear all the Apple announcements from WWDC 2015.

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