Nicola Sturgeon has made little attempt in recent years to hide her desire for the top job in Scottish politics and her dream is now within reach.

The SNP deputy leader had spent five years as health secretary when Alex Salmond reshuffled his Cabinet in September 2012 to give her more responsibility for the referendum.

Since then she has toured the television studios pushing the Yes campaign message and, in the process, bolstered her profile UK-wide.

Within an hour of the First Minister announcing he intended to quit, Scottish bookmakers McBookie.com put Ms Sturgeon at 1/7 favourite to be the next leader and said it would be a "major shock" if the party chose someone else. It would see her make history as the first female First Minister.

Other names may be mentioned, such as local government minister Derek Mackay but it is hard not to imagine Sturgeon being anointed as leader.

Ms Sturgeon, 44, fuelled the inevitable speculation about her intentions when she swiftly declared she could think of "no greater privilege" than to take the helm, although she insisted it was not a decision for today.

She has previously admitted she is keen to get to the top.

"Anybody, in any walk of life, if they are ambitious, wants to get to the pinnacle of their profession," she said.

"So hypothetically of course that is something I would like to think that one day I will get the chance to do."

Ms Sturgeon, who is married to SNP chief executive Peter Murrell, joined the SNP at a young age and is already something of a veteran in Scottish politics.

During her time overseeing the health service she won plaudits for her handling of the swine flu outbreak.

But the reshuffle saw her role switched, and while she became Secretary for Infrastructure, Investment and Cities, it also gave her a key role in the independence referendum.

Immediately after the appointment she took charge of talks already taking place with the Scotland Office to thrash out a deal over the staging of the historic vote.

When David Cameron travelled north to sign the Edinburgh Agreement with the First Minister in October 2012, Ms Sturgeon also penned her signature on the document.

It was, she said, a ''watershed moment in Scotland's home rule journey''. After joining the SNP when she was still a teenager, it was a proud day for Ms Sturgeon.

''This is a hugely privileged position for anybody to be in,'' she told Holyrood magazine.

''But particularly for someone that joined the SNP at 16 because she believed in independence for Scotland and believed, and still believes, that independence is the way of opening the door to creating the country we all want Scotland to be.

''It is massive in that sense and I feel that absolutely.''

Born in the North Ayrshire town of Irvine, she was educated locally before studying law at Glasgow University, going on to work as a solicitor at an advice centre in Drumchapel, one of Glasgow's deprived areas.

She was the youngest candidate in all of Scotland when she first stood for Westminster in the 1992 general election, fighting the Glasgow Shettleston seat.

Ms Sturgeon tried again to win a seat in the Commons when she stood for election in 1997 - the year Tony Blair swept to power, wiping out the Tories in Scotland. The Glasgow Govan seat she contested was the only one north of the border to see a swing away from Labour.

Two years later, in 1999, the first ever Holyrood election was held. Ms Sturgeon was one of the new MSPs, representing the Glasgow region at first but later winning first the Glasgow Govan then the Glasgow Southside seat in 2007 and 2011 respectively.

Holyrood gave her a greater chance to shine, with Ms Sturgeon taking on front bench posts within the party, speaking on issues such as justice and later health.

In 2004, when John Swinney quit as SNP leader, she threw her hat into the ring for the top job. But when Mr Salmond announced he would stand for a second time - he had led the Nationalists for a decade between 1990 and 2000 - she became his running mate, standing for the position of deputy leader.

Mr Salmond was elected leader, but as he did not have a seat in the Scottish Parliament at the time, it was Ms Sturgeon who headed up the party in Holyrood, taking on Labour's Jack McConnell at the weekly First Minister's Questions clashes.

These exchanges helped give her a reputation as a formidable politician - a reputation that has stayed with her.

She revealed at an SNP conference that when she had her first meeting with Scotland Office minister David Mundell as part of the referendum negotiations, his mobile phone rang, with a call from his mother checking that he was okay.

After a television debate on independence with Scottish Secretary Alistair Carmichael last year, political commentator Fraser Nelson wrote that the clash had seen ''a genteel Liberal Democrat being disembowelled by a ferocious and merciless Nationalist'', adding: ''She seemed to quite enjoy it.''