Will Theresa may’s relationship with Donald Trump be specially good or bad?

Hello from Heathrow, where I am waiting to board TereasyJet as an observer on the Prime Minister's first mission to meet Donald Trump.

The stakes for Theresa May are high.

She wants and needs from the new president:

• A promise of early practical steps towards a trade deal that isn't too heavily weighted in America's favour (a big danger), and that can be sold as showing that our Brexit prospects are glittering.
• A belated commitment from him to NATO and its principle that an attack on one member is an attack on all.
• A shoulder-to-shoulder photo-op that looks warm and natural — which seems almost impossible given that that their values and beliefs are worlds apart.

She also somehow has to distance herself from those of his policies that she would see as toxic — such as his restatement overnight of how he would like to see torture re-introduced as an interrogation technique by the security services — without offending a world leader more thin-skinned than perhaps any in history.

It is obviously encouraging for her that she is the very first government head Trump has opted to meet as President.

But being first, the guinea pig, is fraught with risks.