Theresa May will meet Carwyn Jones in Downing Street to talk about Brexit at a time when relations between the two governments are extremely tense.
The First Minister has been publicly critical of the UK Government's negotiations with the European Union and has accused ministers of making a 'power grab' of EU rules and regulations affecting devolved areas.
The talks will be the first between the Prime Minister and First Minister since a brief meeting when the two leaders signed the Swansea Bay City Deal in March.
Theresa May has repeatedly promised that the devolved governments will be fully consulted for their views both on the Brexit talks themselves and the effects of the Withdrawal Bill and there has been a series of meetings at ministerial level. Her deputy, Damian Green, has met the First Minister as has the Brexit Secretary David Davis.
Despite those talks, the Welsh Government remains opposed to the Withdrawal Bill which it claims will seize powers in devolved areas such as fishing and farming when those powers return from the EU. It says it will advise AMs to deny consent to the Bill as it affects Wales, threatening a constitutional crisis.
The UK Government has repeatedly said that it will transfer as many powers as possible to Wales, Scotland and Northern Ireland but insists that some rules and regulations must continue to operate on a UK-wide basis or risk creating problems for business within the United Kingdom.
So the standoff remains althoughthere were signs of progress following a recent discussion between Carwyn Jones and Damian Green.
Carwyn Jones has taken an increasingly high profile rôle at a UK-level in criticising both the negotiations and other aspects of Brexit. Following a meeting last week with another leading Brexiteer he took to Twitter to warn of a 'worrying lack of progress.'
It means the two leaders have a lot of difficult issues to work through when they meet in Downing Street later today.