John Swinney declared “I’m no caretaker” as he launched his bid to become the new leader of the SNP and Scotland’s next first minister.

With Humza Yousaf having announced he is stepping down from the role, Mr Swinney – who served as deputy first minister for more than eight years under Nicola Sturgeon – became the first candidate to declare he is running for the post.

There have been suggestions Mr Swinney would take on the role on an interim basis, but he insisted he will lead the party through this year’s Westminster election and the next Holyrood poll in 2026 as well.

Speaking as he launched his leadership campaign in Edinburgh on Thursday, Mr Swinney made clear: “I am no caretaker. I am no interim leader.

“I am offering to lead my party through the Westminster elections and to lead us beyond the 2026 elections – two contests which I intend to win for the SNP and for Scotland.

“My message is crisp and simple – I am stepping forward to bring the SNP together, deliver economic growth and social justice, to deliver the very best future for everyone in a modern, dynamic, diverse Scotland.”

He also told supporters: “I want to unite the SNP and unite Scotland for independence,” as he conceded the party is “not as cohesive as it needs to be”.

Humza Yousaf announced on Monday he is stepping down as First Minister – a move sparked by his decision to end the SNP’s powersharing deal with the Scottish Greens (Jane Barlow/PA)

Mr Swinney launched his leadership bid a week after Mr Yousaf tore up the powersharing deal the SNP had with the Scottish Greens at Holyrood – a move which led to him announcing on Monday he is to step down from the post just 13 months after taking over from Ms Sturgeon.

With the party now facing the prospect of a second leadership contest in just over a year, Mr Swinney insisted he could “bring the SNP back together again” and “get us focused on what we do best”.

Mr Swinney joined the SNP as a teenager and served as an MP at Westminster before becoming an MSP when the Scottish Parliament was established in 1999.

After the SNP won power in 2007, he then served in the Scottish Government for 16 years, stepping down as deputy first minister only last year when Ms Sturgeon resigned.

He was SNP leader between 2000 and 2004, but stepped down in the wake of the party’s performance in the European election that year.

Former Scottish finance secretary Kate Forbes will confirm later on Thursday if she is to run for the SNP leadership (Jane Barlow/PA)

Mr Swinney insisted: “Having served as a senior minister for 16 years, having helped steer Scotland so close to independence in 2014, I want to give all I have in me to ensure the success of our cause.

“I believe I have the experience, the skills and I command the trust and the confidence of people across this country.”

He praised his potential leadership rival Kate Forbes – who is expected to declare later on Thursday if she will stand for the post.

Mr Swinney described the former Scottish finance secretary as an “intelligent, creative, thoughtful person who has much to contribute” to public life.

Promising she would play a “significant part” in his team, he added: “If elected I will make sure Kate is able to make that contribution.”

Mr Swinney has already attracted significant support from his party for his bid to be its next leader – with Westminster leader Stephen Flynn, Scottish Health Secretary Neil Gray and Scottish Education Secretary Jenny Gilruth amongst his backers.