We have been made aware of an issue with our upstream provider and routing issues affecting some ported numbers within the BT core network.
BT are working on this issue currently and hope to have the problem addressed shortly
Please accept our apologies for any inconvenience caused by this matter which is outside of our control (being within the BT core network)
UPDATE
We have been advised that the IPEX issue which caused EE & O2 calls to ported numbers to fail yesterday was fixed at 06:00 this morning.