From Visa.co.uk -
Are contactless payments using Apple Pay, subject to the £20 contactless threshold?
No – Mobile payment services such as Apple Pay can be used for payments over the £20 contactless threshold, with a growing number of UK retailers supporting what we term ‘high value’ mobile contactless payment – which involve you verifying yourself using Touch ID (for Apple Pay) or another verification method, such as a passcode entered on your device. These cardholder verification methods add an additional layer of security for peace of mind, and act in much the same way as when you use ‘Chip and PIN’ to secure payments made in store with your Visa card. High value mobile payments are also widely supported in a growing number of retailers accepting contactless payment across Europe.