London has been far too timid in response to border tactics

The visit is happening amid ongoing turmoil in London, although it is notable that she has survived now in office for two years, and for a full year after her disastrous general election result.

Few pundits would have expected such endurance after the poll disaster of last June, and it might even be that Mrs May herself would have preferred to quit, but stayed on out of duty (as opposed to wishing to cling to office).

But while it is clear that the failure to win a Conservative overall majority has greatly reduced her capacity for manoeuvre, there is a respect in which the government has been timid to the point of weakness.

The Irish government under Leo Varadkar and Simon Coveney has fully sided with Brussels in the talks and brought closer a situation in which a Brexit no deal might happen.

While Dublin quite reasonably points out that it never wanted Brexit, and that there is at least a moral onus on the UK to help find solutions to the undeniably tricky question of the Irish land border, under Mr Varadkar it abandoned Enda Kenny’s pragmatic approach to the issue.

The rhetoric has been relentlessly hardline and the Irish have pushed for a backstop ‘solution’ that would lead to an Irish Sea border. Almost the only prominent British politician who has bluntly criticised Mr Varadkar’s approach has been Jacob Rees Mogg MP, in this newspaper in March.

Yesterday Boris Johnson dismissed Mrs May’s facilitated customs plan for the Irish border and said his own suggested technical solutions had not been properly examined.

Now Mr Varadkar has said his government plans to “change gear” in how it deals with Brexit. So too should the prime minister change gear in response to Dublin. If the latter is becoming more constructive, that is welcome. But if it is not then as Mr Rees Mogg implied, here must be consequences.