It has not been confirmed that it will be hosted in the UK, just that there are going to be discussions with the BBC about the potential of it being hosted in the UK.
Would be great if it was! The full statement can be seen here:
Manchester seems the obvious choice, they have never hosted it and definitely have venues with sufficient capacity.They need a venue which has the availability for 3 weeks I understand, in order to accommodate the build up and heats.
Since Manchester will have two of he largest arenas in Europe by that point, it does seem to be a decent fit, if they have the ability to rejig events between the two similar venues.