THE future of the United Kingdom is being placed in “peril”, Keir Starmer will declare in his keynote speech to Labour's conference on Wednesday.

Starmer will also insist that Labour is the “party of the Union”.

The Labour leader will use his speech to the party’s Brighton conference to argue that keeping the union of four nations together is not just beneficial in economic terms, but makes for a “more progressive” nation.

It comes after Labour voted not to support calls for Westminster to use a proportional representation voting system, rather than the First Past the Post which has seen the Tories in power for the last decade. 

While Starmer will insist that be believes in the “union of the nations on these islands”, he will warn that there is a “cavalier government that is placing it in peril”.

READ MORE: George Kerevan: Where Labour's conference went so badly wrong for Keir Starmer

The Labour leader will go on to attack Nicola Sturgeon’s SNP government at Holyrood, criticising it on issues such as the education attainment gap and the record number of drugs deaths recorded in Scotland last year.

Starmer will claim at conference that “Scotland is in the unfortunate position of having two bad governments”, with the Tories in power in Westminster and the SNP at Holyrood.

He will say: “When Nicola Sturgeon took office she said she wanted to be judged on her record.

“These days, with the poorest in society less well educated and less healthy and the tragedy of so many drug-related deaths, we hear rather less about the SNP’s record.”

Both the Tories and the SNP seek to “exploit” the divisions over Scotland’s constitutional future “for their own ends”, he will claim.

In contrast, Starmer will insist that “Labour is the party that wants to bring our nations together”.

He will tell supporters: “Under the fantastic leadership of Anas Sarwar, Labour is the party of the Union. Because it’s not just that divorce would be a costly disruption, though that is true.

“And it’s not just that our union is in all our economic interests, though that is also true. It’s that we are more progressive together. We are more secure together.”

The address comes after Scottish Labour leader Anas Sarwar said that his party was only pretending to function during the Holyrood election which saw it return a record-low number of MSPs.

It will top off what has been a dreadful conference for Starmer, made worse by the public resignation of one of his frontbench earlier in the week.

Starmer has been attacked by members and MPs for reneging on the "ten pledges" he made while campaigning to be elected party leader.