Nicola Sturgeon’s shock resignation announcement leaves an extraordinary gap in Scottish and UK politics.

Whoever becomes her successor as SNP leader will face a number of difficult challenges which, until now, have been the domain of Ms Sturgeon.

Here are some of the key tasks for whoever steps into her shoes, becoming leader of Scotland’s dominant political party and the country’s First Minister.

Defining a route to independence

Scottish independence is the SNP’s raison d’etre, and the party was due to have a special conference in March to decide exactly what proposition it would put to the electorate.

But that conference is now in doubt, with Westminster leader Stephen Flynn saying it should be postponed while a new leader is chosen.

In the wake of repeated refusals from Westminster for a second independence referendum, Ms Sturgeon’s preference was to treat the next general election as a de facto referendum.

The next leader will not be obliged to follow the same course. An alternative could be to treat the next Holyrood election – due in 2026 – as a de facto referendum.

Whatever choice is made, there is also the challenge of translating any election win into a mandate for independence.

What to do about gender recognition reform

The Gender Recognition Reform Bill has sharply divided opinion in the SNP, several of its politicians are vocal critics and a minister resigned from Ms Sturgeon’s Government over the issue.

It became a constitutional dispute when the UK Government took the unprecedented step of using Section 35 of the Scotland Act to block the Bill from becoming law, despite a majority of MSPs voting for it.

The stage seemed set for another courtroom clash between the Scottish and UK governments, but the next SNP leader may wish to take a different approach.

They could drop the Bill altogether or try to amend it in a way which would satisfy the UK Government.

Either of those options would leave many in the SNP and their allies unhappy.

National Care Service

Creating a new, centralised care system in Scotland is meant to be the most significant public service reform since the foundation of the NHS.

As it goes through the design and consultation phase, a number of groups have raised alarm that its costs could spiral and its exact role is yet to be defined.

Ms Sturgeon’s Government has insisted the reform is needed and would be a fitting legacy of the Covid pandemic.

MSPs are due to vote on the Bill which would create the National Care Service later this year.

Opposition MSPs want the plans to be paused or dropped altogether.

Deposit return scheme

Another Scottish Government initiative, a bid to introduce a Scotland-wide deposit return scheme (DRS) for drinks containers to encourage recycling, has also attracted anger from industry figures.

A cross-party group of MSPs has said it would be “reckless” to go ahead with it in August this year as planned.

However the Scottish Green Party, whose co-leader Lorna Slater is responsible for introducing the DRS, is determined to go ahead with it.

Strikes and budget pressures

Public services in Scotland and around the UK have been rocked by strikes, with a long-running industrial dispute with teaching unions remaining unresolved.

It comes amid pressure on the Scottish Government budget, with Deputy First Minister John Swinney saying “assiduous” efforts are being made to prevent overspend.

Taxes will be raised in the next financial year, but inflation will continue to pose difficulties for Scotland’s finances.

Education and the NHS

The SNP has committed to reducing the poverty-related attainment gap in Scottish schools, but critics say ministers have failed to live up to their promises.

Meanwhile, Scotland’s NHS is only just starting to recover from an extremely difficult winter which saw A&E waiting times reach record levels.

Improving results in these key areas will be a crucial challenge for the next First Minister.