Labour is on track to come third in both Scottish and Welsh elections next month, new polling shows.
Research by More in Common suggests Labour will lose seats in both the Scottish Parliament and Welsh Senedd on 7 May to plunge Keir Starmer deeper into crisis.
An MRP (Multilevel Regression with Post-stratification) model, based on polling of more than 5,000 Scottish voters, found Labour will slump to just 17 seats at Holyrood.
When the Prime Minister won power in July 2024, he had high hopes Labour could go on to win this year's Scottish Parliament elections.
But the model shows the SNP remaining as the largest party at Holyrood, despite being squeezed by other parties and falling short of a majority.
The SNP were projected to win 56 seats next month, meaning they are likely to be reliant on the support of the Scottish Greens (8 seats) to govern.
The model also found Reform UK are set to win 22 seats at Holyrood, putting Nigel Farage's party ahead of Labour, the Liberal Democrats (14 seats) and the Conservatives (12 seats).
Meanwhile, a separate MRP model by More in Common showed Plaid Cymru will be the largest party in the Welsh Senedd next month.
Research by More in Common suggests Labour will lose seats in both the Scottish Parliament and Welsh Senedd on 7 May to plunge Keir Starmer deeper into crisis
The model, based on polling of more than 2,500 Welsh voters, found Labour is set to be pushed into third place - behind Plaid and Reform - after 27 years in government in Wales.
Plaid are projected to be the largest party with 30 seats, with Reform close behind with 28 seats - meaning they are set to form the official opposition in the Welsh Senedd - and Labour reduced to just 24 seats.
It means Wales is on track to have its first non-Labour first minister since devolution in 1999.
The model also found the Greens are likely to win their first seats in the Welsh Senedd, with Zack Polanski's party picking up four seats.
The Conservatives could end up with just seven seats, while the Lib Dems will win three seats, according to the research.
Despite Plaid's projected victory, the nationalist party is set to fall 19 seats short of the 49 seats needed to form a majority in the Welsh Senedd.
The MRP model suggests a Plaid-Labour coalition could be the only viable route to forming a government in Cardiff.
Luke Tryl, executive director of More in Common UK, said: 'Looking at Wales today, it’s hard to believe that the 2024 general election was less than two years ago.
'The political map has changed so dramatically since Labour won decisively in Wales.
'Plaid Cymru are the clear beneficiaries of a country ready for change, and could be on course to lead a Welsh Government for the first time.
'But it may be a tricky start - potentially requiring sharing power with a weakened Labour Party that, despite its losses, could still wield considerable influence over the shape of any coalition.'
Mr Tryl also said More in Common's polling showed Reform have 'firmly displaced the Conservatives as the party of the Welsh Right'.
He added that the MRP model based on Scottish polling showed the balance of power at Holyrood 'on a knife edge between a pro-independence and pro-unionist majority'.
More in Common polled 5,124 Scottish voters between 4 February and 10 April, and 2,519 Welsh voters between 30 January and 10 April.