BT went behind Sky's back and did a deal direct with Cricket Australia to have the exclusive rights to all of Australia's home tests & BBL. This deal then effects Sky's deal with the ECB to show all England tests as BT Sport have the exclusive rights with the host broadcaster.
Im not sure it really counts as "going behind Sky's backs" there are usually invitation to tender notices sent out for things like this, i suspect BT offered more money than Sky did presumably off the back of trying to disrupt the next domestic cricket rights bidding too. Not sure how long BT's deal is for but will be interesting to see if they try to retain these rights if they havent cracked the domestic market.
Does make me wonder how Sky think they can fill an entire cricket channel throughout the winter, i know they have a raft of their own produced content with the masterclasses and what not but can see the cricket channel being very repetitive over the next few months!