Angela Merkel has upset the new leader of her Christian Democratic party (CDU) party by cancelling a key hustings for the European elections, leading to speculation that the two leading figures in German politics have fallen out over the party’s new identity.

Ms Merkel has informed Annegret Kramp-Karrenbauer at the eleventh hour that she will not travel to Munster to jointly open the CDU campaign for May’s European elections, Welt am Sonntag reported on Sunday.

The last minute snub is a major embarrassment to Ms Kramp-Karrenbauer, who had already informed party colleagues that the Chancellor was to appear and ordered corresponding security measures to be taken.

It is just the latest in a string of rebuffs from Ms Merkel to the woman once labelled “mini-Merkel” who succeeded her as party leader at the end of last year.

The Chancellor has reportedly informed her heir apparent she will not take part in any future political campaigning, even as the party faces key state elections in the autumn.