Ms Dugdale’s personal ratings are also plummeting according to the Ipsos Mori poll for STV which indicates that the SNP remains on course for the easiest Scottish Parliament election win since devolution with another majority.
Labour published its manifesto in Edinburgh yesterday, with Ms Dugdale pledging a return to Labour’s “roots” in an appeal to undecided voters.
“I want to speak directly to them as they make up their mind on how to use both their votes,” she said. “If you are still unsure how to vote, here’s our plan: We’ll tax the richest 1 per cent so we can invest in schools and stop the cuts to our NHS and public services.”
But the new poll indicates Labour will get 20 seats next week with the Conservatives on 23. It would mark the best result for Ruth Davidson’s party since devolution – and an all-time low for Labour.
The manifesto pledges to protect spending on health, education, policing, as well as arts and culture.
And the party will use the new powers coming to the Scottish Parliament to increase income tax by 1 per cent across the board, with the top rate for those earning more than £150,000 going up from 45p to 50p.
Ms Dugdale insisted Labour was the “only party offering an alternative to austerity”.
She added: “This is a manifesto in the best traditions of the Labour Party. “It is the return of the Labour Party that gave us the NHS, the minimum wage, the Labour Party that established the Scottish Parliament.
“It is a positive plan that returns to Labour’s roots and invests in our nation’s future. Our manifesto isn’t about the politician on the front cover. Our manifesto is about the people of Scotland.”
Three-quarters of Scots back the plan to increase the higher rate of tax to 50p, the Ipsos Mori survey shows, while more than half (52 per cent) back the 1p hike in income tax proposed by Labour.
Questioned on her poor polls, she said: “The problems with the Labour Party didn’t happen overnight and they’re not going to be fixed overnight.
“I said when I put my name forward for the leadership of the party that I have a plan to turn things round and I believe I have delivered on that plan.”
She cited Scottish Labour’s “clearer sense of values”, its plan to tax the rich to “stop the cuts”, her elevation of new candidates and its greater autonomy from the UK party.
Labour has ruled out another independence referendum for the lifetime of the next parliament and confirmed its opposition to the renewal of Trident.
Both policies have caused difficulties for Ms Dugdale as she has indicated she will not stop her members campaigning for independence and that she backs Trident.
She insists there has never been a prohibition on Labour members campaigning for independence.
“There was no whip last time, so nothing has changed in that regard, but every Labour MSP campaigned in that referendum for a No vote,” she said.
“People believed Nicola Sturgeon when she said it was a once-in-a-lifetime, once-in-a-generation, referendum.”
The STV poll published yesterday gave Ms Dugdale a net satisfaction rating of -11 per cent, down from +5 per cent in February.
In contrast, Ms Davidson has a net satisfaction rating of +15 per cent, up seven points.
Ms Davidson said: “This is an encouraging poll for us. We now intend to work harder than ever over the next week to show people we can be the strong opposition to the SNP our country needs.”
First Minister Nicola Sturgeon remains the most popular leader on +36 per cent.