The Tories are still jubilant at what they regard as the gift of Jeremy Corbyn's election. But they recognise that he may not be the opponent they face in 2020 (though several MPs told me they expected him to last). When George Osborne remarked that Labour could have held two leadership contests by the general election it wasn't entirely clear whether he was joking.

In the bars of Manchester this week, the Tories found time to discuss Corbyn's potential successors. The name most often cited to me as a threat was that of Dan Jarvis. "We'd never be able to accuse him of being weak," one minister said of the former paratrooper, who served in Afghanistan and Iraq. Having rejected appeals to stand last time round, the Barnsley Central MP is now the favourite to succeed Corbyn.

The question often asked of Jarvis in Labour circles is "what does he stand for?" He is not identified with any wing or faction of the party (recently stepping down as a vice-chair of Progress) and, though casually dubbed a "Blairite", he leans leftwards on issues such as tax. Several Tories identified this relative amorphousness as a strength, noting that Tony Blair and David Cameron travelled similarly light. But Jarvis, who has returned to the backbenches, is likely to acquire greater definition, with a lecture on the economy planned.

It is because they believe Labour has capable leaders in the wings that the Tories are determined to contaminate the entire party's brand. Rather than referring to "Jeremy Corbyn", they spoke in their speeches of "the Labour leader", seeking to eliminate the distance between him and his MPs. Their aim is to ensure that the damage inflicted on the opposition is so great that there will be no possibility of a recovery in this parliament or, some hope, in any one. As I note in my column this week, the ambition is not merely to win in 2020 but to put Labour out of business for good.