Election 2017: Will the SNP be targeting seats?

David Mundell, Alistair Carmichael and Ian Murray were the only non-SNP winners in 2015

The SNP's result at the last general election was extraordinary. They won all bar three of Scotland's constituencies - a gain of 50 from 2010. Scotland's electoral map turned almost completely yellow. But what about this time?

There are some key areas where opposition parties are lining up challenges; the borders and north east from the Conservatives, East Dunbartonshire and Edinburgh West from the Lib Dems and East Renfrewshire, where Nicola Sturgeon was campaigning today, from Labour and the Tories.

I wrote earlier this week about the race for Moray, where the SNP's deputy leader is the incumbent.

We'll have more on what the other parties think over the weekend. But the SNP have said they will be fighting hard to win all 56 seats they took in 2015 and insiders hope the profile of local MPs will help them in many of these areas.

What about the three seats they failed to take last time?

Scottish Secretary David Mundell would be the biggest scalp for the party. He has held the Dumfriesshire, Clydesdale and Tweeddale seat since it was created in 2005 - but in 2015 his majority was reduced to just 798, one of the smallest in Scotland.

SNP insiders admit this is an area the Conservatives appear to be doing well in, but they will try and target Mr Mundell on UK government policies they think are unpopular. And some hope to take anti-Brexit votes from Labour.

It's excepted Mr Mundell will spend most of the election focussing on this seat rather than the wider Scottish campaign - people close to him say he knows he'll have to work hard to win here.

The SNP came close to sweeping the board in 2015

Ian Murray's Edinburgh South is another constituency the SNP have an eye on.

Mr Murray actually increased his majority in 2015. In 2010 he beat the Lib Dem candidate by a tiny 316 votes - last time he beat his SNP challenger by 2,637.

SNP sources say they are optimistic here - not least because they think increased support for the Conservatives could take votes away from Mr Murray. But if Labour has a heartland left in Scotland this is it - they hold the equivalent Holyrood seat too. The party will put a lot into this seat.

Finally there's Orkney and Shetland, held by Liberal Democrat former Scottish Secretary Alistair Carmichael last time.

Shortly after that win, Mr Carmichael was embroiled in a row after he admitted backing the leak of a document which suggested Nicola Sturgeon wanted David Cameron to be PM (a claim she furiously denied, and which there's no evidence for).

He faced calls to resign and was taken to a special election court by campaigners. Judges say he lied about when he knew about the memo in a TV interview, but ruled it wasn't beyond reasonable doubt he'd committed an illegal practice.

So could his position be under threat? Lib Dem strategists are confident they'll hold it. They highlight their candidates in Orkney and Shetland increased their majorities at the Holyrood election last year. Though if the past 12 months have shown us anything, it's that nothing is certain in the political world.

• The SNP is expected to name its candidates for the seats it didn't win last time, plus Edinburgh West and Glasgow East, later this week. We'll have a full list of candidates online after the close of nominations.