I’M sure every Labour MSP has heard the old adage about not airing your dirty linen in public, but they don’t seem to pay it any heed.

Time and time again the party gives its opponents the opportunity to criticise it for splits among senior figures.

The SNP lap it up and waste no time in using it against them.

But when Labour is pretty much handing its rivals bucketloads of mud, what else will they do but sling it?

The latest came this week as Alex Rowley, interim leader no less, was taped admitting he and left wing colleagues had been planning for Kezia Dugdale’s departure and had decided Richard Leonard was their man.

At First Minister’s Questions, Nicola Sturgeon was not going to let the weekly set piece session pass without comment on Labour’s latest woes.

So she, somewhat clumsily, shoe-horned jibes about Labour into an answer about free bus passes for older people.

The question came from none other than leadership contender Richard Leonard.

Ms Sturgeon was pulled up by the Presiding Officer for straying from the territory of the question but she didn’t care about that, the damage had been inflicted, on the record.

Briefings and statements have been bandied about with Labour MSPs from each campaign publicly criticising the other, some in what can only be described as unparliamentary language.

Of course, Labour has form in this regard.

Ms Dugdale said it was the sort of “internal squabbles” she had tried to sort out when leader. Obviously her efforts were in vain.

Then the former leader herself handed the SNP a pile of ammunition previously when she got involved in the UK Labour leadership election when she said Labour would be left “carping from the side-lines” if Jeremy Corbyn was elected leader.

If Kezia Dugdale had a vote for every time Nicola Sturgeon threw that remark back at her, she would probably have won the 2016 election.

And one of Kezia’s predecessors, Johann Lamont, when she resigned, told the country that Scottish Labour was regarded as a “branch office” by some in London.

Even in the good times, some couldn’t help themselves from letting what should be very private and confidential conversations become public.

In the immediate aftermath of the 2001 UK election win the famous exchange between Helen Liddell and Henry McLeish in which she called John Reid a “patronising bastard” made headlines for days and is remembered long after all three have left the political stage.

Labour is enjoying something of a revival, although it has yet to translate into electoral success in Scotland or the UK.

It is somewhat unexpected by most, but if the party is to capitalise on it and really make a comeback in Scotland and get into power at Westminster, it must shut down the internal squabbling.

Of course, divisions, debates and differences of opinion are all healthy in a political party and those who show none raise suspicions of their own.

But what Labour needs now is unity – otherwise it will lose what ground it has gained.