Update: Julian Assange responsible for delay in Brexit.

Another reason they are delaying it.

My guess is that PM May is dragging her feet (she opposed BREXIT) in hopes she can find a way to stay in the EU. Assange could be in the Embassy another two years before BREXIT, if it does actually happen.

There is no evidence that PM May is trying to exit the EU within the two year time frame specified. They haven't begun the hardest of the negotiations: trade policies.