Today is the test for the exotic Mr Stewart

There cannot be many leadership contests where the candidate with the fewest votes is suddenly the one everyone is talking about. But Rory Stewart, who won the support of just 19 MPS in the first round last week, is being talked about as a possible runner-up to the likely winner Boris Johnson. Or at least he is by many people who do not actually have a say in the matter and who do not necessarily have the interests of the Conservative Party at heart. Mr Stewart allegedly has what the Americans call “the big mo” – he is going forward while his rivals threaten to stall or fall backwards.

The very fact that he is far less well-known than his rivals gives him novelty value. Mr Stewart has been in the Cabinet just a few weeks, taking over as International Development Secretary in May as a consequence of a mini-reshuffle. He has been an MP for nine years, was previously chairman of the defence select committee and has served in a number of departments.

He is known to his colleagues at Westminster in a way he is not to the wider public; and so far fewer than 20 MPS consider him to be a potential leader. That may well change today with the second round of voting, but he still needs to secure 33 endorsements in order to proceed in the contest.

Mr Stewart’s strongest support is coming from outside Westminster among those who do not want the UK to leave the EU and see him as the best prospect for blocking it. His pitch to his colleagues is that he will prevent the no-deal Brexit that Mr Johnson has said he is prepared to countenance. Mr Stewart says some 100 Tory MPS would vote in parliament to stop it happening. He is vying with Jeremy Hunt and Michael Gove for the role of the “stop Boris” candidate.

He has excited interest among the party membership, as evinced by a poll for Conservative Home that placed him second in popularity behind Mr Johnson, and bookies have him as second favourite, which, since he has the lowest support of those left in the race, is surprising.

The point is that not much is known about Mr Stewart other than that he is a classic Foreign Office insider who probably regards Brexit as a national mistake. He has an exotic past, serving in overseas diplomatic posts, though he denied working for MI6 despite rumours to the contrary. We will know later today whether Mr Stewart is a flash in the pan or a real threat to Mr Johnson.