SNP's latest campaign trail calamity highlights the disarray of Scotland's public services

But if John Swinney hoped his trip to the Western Isles was a chance to put the campaign back on track, he reckoned without the steady drumbeat of bad news created by Scotland’s long-running ferry crisis.

A chartered catamaran had been due to take over the Troon to Brodick route from the troubled Glen Sannox, which took the best part of a decade to build, was massively over-budget and now appears to be plagued by faults. Unfortunately, the catamaran returned late to the Clyde from an annual overhaul on Merseyside, with the result that yesterday’s sailings on the route could not go ahead.

READ MORE: Swinney's £10m islands fund 'too little, too late' as CalMac ferry crisis intensifies

These latest cancellations came after extensive disruption to state-owned ferry operator CalMac’s west coast network caused by a staggering total of ten vessels being out of action, the highest number in years. And that fiasco only added to already serious questions about the SNP’s commitment to the proper maintenance of the fleet.

Given the chaos, Nationalist MSP Maree Todd’s decision to post a picture of a CalMac ferry mocked up in SNP colours with the slogan “Vote Todd” on the side – on April Fool’s Day of all days – was ill-advised. And her subsequent decision to delete the image may have made things even worse, as it invited speculation that she had tacitly admitted that the state of Scotland’s ferries is a problem for the SNP.

What will be the next campaign trail calamity, we wonder? Will Education Secretary Jenny Gilruth visit a school just as a mass brawl breaks out in the playground, highlighting the persistent complaints and cries for help from hard-pressed teachers about pupils’ violence, abuse and general bad behaviour?

With public services in such a mess, Scotland is so full of such pitfalls for SNP politicians that they may be difficult to avoid.