Theresa May's bandwagon appears unstoppable, but beware the curse of the Tory frontrunner

Andrea Leadsom's claim to be the new Margaret Thatcher could prove popular with party members

Theresa May arrives for a cabinet meeting at 10 Downing Street in London (AP)

The Theresa May bandwagon is rolling, and appears to be unstoppable. She already has the support of half the 330 Conservative MPs.

But the Home Secretary knows that she cannot be assured of victory yet. She now has a real challenger in Andrea Leadsom, the Energy Minister and surprise package in the Tory leadership contest.

The elimination of Liam Fox, who came fifth and bottom in the first round ballot among Tory MPs, could be good news for Ms Leadsom even though Dr Fox announced that he will now support Ms May.

The 16 MPs who backed Dr Fox, a hardline Eurosceptic and right-winger, are more likely to switch to Ms Leadsom in the next round than go to Michael Gove. Although Mr Gove led the Vote Leave campaign, he is a Cameron-style moderniser on social issues and he has damaged himself by killing Boris Johnson’s leadership hopes.

Stephen Crabb's decision to pull out of the race after coming fourth is another boost for Ms May, as he was swift to say he is now supporting the Home Secretary. He cannot guarantee that all the 34 MPs who supported him in the first round will follow him into the May camp. But several will.

It is going to be hard for Mr Gove to catch Ms Leadsom. So there is now a very real prospect that Britain will get its second woman prime minister in September.

It looks very likely that Ms May and Ms Leadsom will be the top two names after the next two rounds of voting among the MPs, and will then go into the decisive ballot of the party’s 125,000 members. Then, either Ms May or Ms Leadsom would join the lengthening list of women leaders including Angela Merkel, Nicola Sturgeon and, possibly, Hillary Clinton.

The first-round voting figures matter because they tell us more than all the various, and sometimes contradictory, numbers that have appeared in the media since the five runners entered the race.

These are real figures, not spin by the campaign managers or numbers based on false promises by Tory MPs about who they will support in the secret ballot. With good reason, Conservative MPs are described as “the most sophisticated electorate in the world".

When Margaret Thatcher was toppled by her own party after failing to knock Michael Heseltine out of the race in the first ballot in 1990, her team had a long list of broken promises from Tory MPs who deserted her despite pledging support. The joke inside leadership campaigns is that they sometimes have more pledges than there are Tory MPs.

Ms May undoubtedly has the initiative. Her trump card with Tory members may be experience, especially on matters of national security in a dangerous world. She has chaired meetings of the Cabinet’s emergency committee Cobra; Ms Leadsom is not even in the Cabinet yet.

Tory members backed Cameron by a 2-1 margin over David Davis, a right-winger and Eurosceptic, in 2005. Europe was not the big issue then and the party was in opposition rather than government, so the members could take a chance on the next generation and Mr Cameron’s modernisation project.

The 2005 result suggests that the dividing line between Remainers and Leavers may not loom so large in the mind of today’s members as we might expect. Although Ms Leadsom’s unashamed pitch as the new Margaret Thatcher will appeal to many party members, Ms May’s position as a Reluctant Remainer may damage her less than Ms Leadsom hopes.

However, Ms May will be only too aware that the curse of the front-runner, which afflicted Michael Heseltine, Kenneth Clarke and Mr Davis in previous Tory contests, could strike again and allow Ms Leadsom to win an astonishing victory. After all, Boris Johnson was the front-runner only six days ago.