SCOTTISH Labour leader Kezia Dugdale will this week support new powers for Holyrood as part of a call for a reformed United Kingdom.

In a major speech, she will back a constitutional shake-up that could see the UK move towards federalism in a post-Brexit era.

Dugdale led her party into third place at the Holyrood election and an opinion poll published last week had Scottish Labour languishing on around 15 per cent of the vote.

Some senior Labour figures believe the under-performance is due to a perception of the party having little to say on the constitution. Dugdale famously flip-flopped on her opposition to independence at the beginning of the Holyrood campaign, a wobble that damaged Labour.

Her deputy Alex Rowley has also been vocal in calling for Labour to back home rule.

However, Dugdale will lay out her thoughts on constitutional issues in a speech on Wednesday at an Institute for Public Policy Research event in London.

It is understood the location signifies that the content will address constitutional reform not just in Scotland, but across Britain. She is believed to be more sympathetic to federalism, which involves UK-wide reform, than home rule, which is Scotland-only.

Dugdale is expected to speak about which powers currently held by Westminster and the European Union could be devolved, as well as addressing the consequences of Scotland's pro-EU vote.

Her speech, which will define Scottish Labour’s position on the constitution in the years leading up to the next Holyrood election, will attempt to pitch Labour politically between hard Brexit and independence.

In the summer, Dugdale said she was looking at UK-wide federal solutions that respected Scotland's pro-EU position: "What I am arguing for is there may be a possibility that Scotland could retain its place both in the UK and in the EU through a potential – and I have to say this tentatively – a potential federalist solution which could see us achieve that.

"It's important I focus on that and I explore those options, because actually that's what the vast majority of people in Scotland want - that's been reflected in two referendum results."

It was reported that Lord Falconer, Labour's former justice secretary, was exploring the options for federalism.

However, only the Westminster Government could deliver federalism and it is unclear whether UK Labour leader Jeremy Corbyn would be behind such a move.

Scottish Labour has adopted a number of stances on extra powers over the years, but the party has not been rewarded electorally.

Speaking ahead of the event, Scottish Labour Europe spokesman Lewis Macdonald said: "More than five months since the EU referendum, two things have become clear: The Tories have no plan for Brexit and are willing to risk a hard exit from the EU, and the SNP has no plan other than to divide our country even more with a fresh push for Scottish independence. We don’t need more division – our country is already divided enough.

"The people of Scotland deserve better than two hard choices at the extremes of the constitutional debate. In her speech this week, Kez Dugdale will set out a vision for our Union.”