It is rare for a government to lose such a senior minister in the manner Derek Mackay resigned.

He was the man Nicola Sturgeon catapulted into the vacancy created when John Swinney was moved to take charge of education.

Since his election as an MSP in 2011 he was on the path to high office.

Indeed, until yesterday it would have been hard to find anyone involved in Scottish politics to not reply “Derek Mackay” when asked who would succeed Nicola Sturgeon whenever she vacates the SNP leader’s office.

READ MORE: In full: The messages that led to Derek Mackay's downfall

Mr Mackay was one of the youngest council leaders when he headed up Renfrewshire Council from 2007 to 2011.

He was quickly installed as Local Government Minister by Alex Salmond just seven months after his election to Holyrood.

He was then moved three years later to the difficult brief of Transport Secretary, and then promoted by Nicola Sturgeon to arguably the second top job in Government.

He was the SNP chairman and business convenor for several years and a party favourite at conference for his often humourous engaging with the delegates.

Every party needs several so called “big hitters” to not only shoulder the burden of leadership but with one eye on the future.

For years Nicola Sturgeon was the undisputed leader in waiting to succeed Alex Salmond.

READ MORE: Scottish finance chief Derek Mackay accused of sending 'inappropriate' messages to teenage boy

Derek Mackay was emerging as a serious contender to carry on the work of Alex Salmond and Nicola Sturgeon, when the time came.

Of course there are others in a position to succeed, notably Justice Secretary Humza Yousaf, Deputy Leader Keith Brown and now Kate Forbes who stepped into Mackay’s shoes at the 11th hour is someone obviously held in high regard by Ms Sturgeon.

But it is the immediate and also longer term implications of Derek Mackay’s fall that will be occupying Nicola Sturgeon’s thoughts.

His actions in his private life could take a wider toll than his resignation.

Scandals damage not just the individual concerned but parties and the SNP will not be immune.

The party made huge gains since devolution by presenting itself as clean and scandal free while Labour and the Tories at Westminster lurched from one headline to another.

The SNP will have to contend with the publicity from of the Alex Salmond trial in just one month’s time.

The prospect of any police involvement in Mr Mackay’s case will not be what Nicola Sturgeon had hoped for as she looks to grow support for independence.

The actions of one man is unlikely to change people’s belief in independence but the chart Nicola Sturgeon is plotting depends on winning a majority victory at next year’s Scottish Parliament elections.

And it is at the ballot box where voters really make their feelings known.