A fool or a knave? That was the question left hanging by Kezia Dugdale's remarkably ill-timed and divisive suggestion that Jeremy Corbyn does not want to bring together Labour's warring factions, after a remarkably conciliatory victory speech from the UK leader yesterday.

Just minutes after Corbyn finished, with him still surrounded by jubilant supporters in the hall, she rushed out a declaration that he faced a "difficult task" healing the party.

Corbyn's plea for unity, for the need to "wipe the slate clean" had been summarily rejected by the Scottish party leader.

After what was probably the most bitter leadership election in Labour's entire history, orchestrated by those who moved heaven and earth to oust him – and Dugdale must count as one of them – she sought to reignite warfare while the participants in the last battle are still licking their wounds. And then she compounded her error by later attempting to row back on her earlier statements.

It was a most unnecessary declaration of hostilities by her and one that will surely come back to haunt her in the weeks and months that follow.

Despite her backing for Owen Smith, she could quite easily have opted for a neutral form of words, simply congratulating Corbyn, wishing him well and offering constructive support.

There are those within Labour's ranks at Westminster who will never accept him leading the party and who have scant respect for the overwhelming mandate won by him. Her words will only stoke their ire.

Dugdale's close association with Labour's only Scottish MP Ian Murray, who was a key player in the summer shadow cabinet coup against Corbyn, will also aggravate such tensions.

The fact that Murray refuses to sit in Corbyn's shadow cabinet at Westminster, but serves in Dugdale's Holyrood-based frontbench, is also a running sore.

Corbyn's most senior supporters, like shadow Chancellor John McDonnell and UK elections chair Jon Trickett, reacted to Dugdale's remarks in reasoned tones. They are to be congratulated.

However, less restrained Corbyn-backers may conclude that by picking a fresh fight with the UK leader, she has shown gross misjudgement. Or is intent on provoking another challenge.

After presiding over the calamity of her party slumping into third place behind the Tories at Holyrood, many Labour supporters will feel that her attentions would be better focused on working for a revival for her party than with picking fresh battles with her Westminster counterpart.

This newspaper supports independence but believes that a strong Scottish Labour party is vital in holding the Government to account. Labour's traditional values have always included unity. By her words Dugdale has betrayed them.