Seems like the government forgot to mention to apple/google that they were interested in their app. Quote from todays times below.
"In a sign of the breakdown in trust between the two sides sources at Apple said that it had not been informed of the announcement or consulted about the plan to work together. “We don’t know what they mean by this hybrid model. They haven’t spoken to us about it,” a source said.
The company also queried the claim that its model was less accurate at measuring distance than the government’s NHSX model. “It is difficult to understand what these claims are as they haven’t spoken to us. But the app has been downloaded by six million in 24 hours in Germany, the Italians have had it going since Monday, the Dutch government and Irish government have it, and there has been no issue about proximity detection.”