THE relationship between Scottish Labour leader Kezia Dugdale and her deputy has completely broken down, according to a senior party source.

Dugdale's friends claim that Alex Rowley has been undisciplined and cannot be relied on to support her.

But her deputy hit back robustly, saying: “I think it’s absolutely shocking. I am not going to get into the gutter. That’s where these people want to be. They are destroying the Labour party.”

The tensions may get worse this month when Dugdale flies to the US for a leadership programme, creating a potential power vacuum.

Labour at Westminster has undergone a traumatic week after dozens of Corbyn's colleagues quit their ministerial posts and called on the left-winger to quit.

Dugdale and Rowley, who were elected leader and deputy leader of Scottish Labour last year, clashed on Corbyn’s future. The split became evident last week when the party’s sole MP, Ian Murray, quit as Corbyn’s shadow Scotland secretary. Despite Murray being a close ally of Dugdale, Rowley accused the MP of putting “self-interest before the needs of the country”.

Dugdale later said it would be “difficult” for Corbyn to continue in post – a clear indication she wants him to resign - but Rowley signed a letter backing the embattled left-wing leader.

One senior Scottish Labour source said: “Their relationship has completely broken down."

A second party insider also queried Rowley’s support for Corbyn: “It’s odd, given that Alex believed Corbyn wasn’t popular on the doorsteps during the Holyrood election.” A third party source said of Rowley: “He couldn’t have been more unhelpful if he had tried.”

Another Dugdale ally believes Rowley has failed to behave like a deputy leader since he won the post. Within days of taking on the role, he called for a referendum on Trident renewal, which is not Scottish Labour policy.

He has also policy freelanced on the constitution by supporting home rule, a position that has not been adopted by his party.

Asked by this newspaper about the party figures who believe he has undermined Dugdale, Rowley said: “Those who would claim that have no foundation for it whatsoever…My criticism is not of Kez.”

On whether he supports Dugdale’s position on Corbyn, he said: “No, I don’t. [Just] because I am the elected deputy leader of the Labour Party in Scotland doesn’t mean I have to endorse a statement that calls for the leader of the Labour Party to go.”

Asked whether he, as deputy leader, should be supporting the leader of the Scottish Labour party, he said: “Against a coup against the leader of the UK party? No.”

Refusing to confirm or deny that his relationship with Dugdale had broken down he said only, “I can’t speak for Kez. All I can say is I will continue to work as the deputy leader.” And asked how his relationship was with her just now he said: “I had a good chat with her this morning.”

Dugdale succeeded Jim Murphy as party leader after winning 72.1% of the vote. Rowley secured 55.4%.

Another party source said: “Alex’s problem is that he is hard of hearing. When the leadership results were announced, he seems to have believed that he was crowned leader.”

Dugdale’s attendance on the US State Department’s International Visitor Leadership Program this month may also create a headache for her party, with relations between the two at a low ebb insiders are speculating about who will lead the party when she is abroad.

It is understood Dugdale will remain in charge while she is away and a rota for Shadow Cabinet members will be in place to provide day-to-day cover.

A senior Scottish Tory source said: "It's no surprise Scottish Labour is responding to the upheaval at Westminster with added chaos of its own. Scottish Labour needs to get a grip, not descend into further turmoil over its internal splits."

An SNP spokesperson said: "At a time of national crisis, with the UK economy in turmoil following the EU referendum result, political parties have a duty and a responsibility to step up to the mark, show some leadership, and work to find a way forward. It is shameful that both the Tory UK government and the Labour opposition have instead chosen to abdicate their responsibilities. They have no plan and rather than uniting to come up with one they are indulging in infighting and naval gazing at the expense of the country."