Nicola Sturgeon is facing the biggest test of her political career when she gives evidence to the Holyrood inquiry investigating claims of sexual harassment against Alex Salmond.

Her political opponents are planning to submit a vote of no confidence in her leadership amid claims she misled parliament, but today's session will give the First Minister her chance to have her say.

She has said she is "relishing" the opportunity, but claims and allegations continue to swirl around her following the release of legal advice to the Scottish Government as it tried to fight a judicial review into investigation into Mr Salmond.

The former First Minister has already given his evidence to the committee, but what are the key questions facing Ms Sturgeon?  

Did she break the ministerial code?

This allegation is a resignation matter for Ms Sturgeon, her politicial opponents insist. 

Questions hang over when the First Minister found out about the investigation into her predecessors over the harassment claims. She initially said this happened on 2 April 2018, it has emerged there was another meeting on 29 March with Mr Salmond's asdvisor Geoff Aberdein, where details of the case were discussed.

READ MORE: Nicola Sturgeon to face questions at Salmond inquiry amid calls to resign

If Ms Sturgeon knew what the second meeting was about, she would have known it was government business and she should have reported it to civil servants at the time. But this did not happen.

Mr Salmond has said Ms Sturgeon is guilty of several breaches of the code in relation to these meetings. Ms Sturgeon has denied breaking the code.

The Herald:

The scandal hangs on the investigation into Alex Salmond

Why did the investigation into Alex Salmond collapse?

This is what the committee is chiefly investigating. They are trying to find out what led to the introduction of a policy which Mr Salmond successfully challenged in court.

It's been argued the policy was introduced too quickly and failed everyone involved; Mr Salmond and those who accused him of harassment.

It has been said that the investigating officer was too close to the complainants - a big mistake from the government, which has been admitted.

Why did the government continue to defend its case?

The Scottish government initially defended the harassment policy in the face of Mr Salmond's legal challenge.

On Tuesday night it finally published its legal advice, which shows concerns were raised by its legal adviser - in October 2018.

READ MORE: Nicola Sturgeon evidence session at Holyrood - how to watch

In December, external lawyers said the "least worst" option would be to admit defeat. The case wasn't conceded until January 2019.

This has raised questions over whether the government should have made that decision earlier - and potentially saved a lot of money in the process.

Mr Salmond claims this is also a breach of the ministerial code. 

The Herald:

Ms Sturgeon will speak to the inquiry today

Did the Scottish Government leak sensitive information?

Mr Salmond has claimed that the name of one of the complainers in his case was leaked by a 'senior Scottish government official' 

This has been backed up by two other witnesses - Roddy Dunlop, the former SNP MSP and QC, and Kevin Pringle, Mr Salmond's spin doctor. Revealing the name would be a significant breach of confidentiality.

Ms Sturgeon has said she didn't think it happened "to the best of her knowledge", but Mr Salmond has claimed there were witnesses who can prove it.