We are told the Prime Minister will not be taking any questions during the trip, but if he were, you can guarantee they would be some of the unanswered questions surrounding the former Welsh Secretary.
Mr Cairns is now the subject of a civil service investigation into whether or not he broke the ministerial code in what he said about the involvement of a close aide in the collapse of a rape trial.
However, he remains under pressure to stand aside as a candidate in this General Election, something he is so far refusing to do.
As Welsh Secretary he was due to lead the campaign in Wales and, as yet, there is no sign of a replacement. Which senior Welsh Tory figure will be by the Prime Minister’s side today?
It is easier to explain why Boris Johnson’s first visit to Wales is to the north-east of the country.
Seats there are high on the Tory target list and our most recent Welsh poll showed that if the election goes its way, the Conservative party could hope to take Alyn and Deeside, Delyn, Vale of Clwyd and Wrexham from Labour.
But they hoped the same thing in 2017, even when the wheels were falling off the campaign elsewhere. Late on election night, one Welsh Conservative told me the north-east would be “our saving grace”. It wasn’t to be.
Some in the party in Wales are nervous that, despite that experience, too much hope is being pinned on winning those seats again, to make up for expected losses in Scotland.