ED Miliband will insist today only Labour can save the UK as he seeks to assure the British public he can make the transition from leader of the opposition to prime minister.

Prior to his keynote address to the party conference, Margaret Curran, the Shadow Scottish Secretary, will say Scotland is now "in the fight of our lives" to save the UK.

She will tell delegates "Scots are trapped between two governments that have their priorities all wrong" – the Nationalists in Edinburgh and the Conservatives in London, both of which promote the "politics of division".

In his keynote address this afternoon, Mr Miliband will stress the same theme, saying Scottish Labour is the only political force that can defeat the SNP, branding David Cameron and the Conservatives as the party which divides the country.

The Labour leader will argue against the separation he says Scottish independence would instil and in favour of common-ality, saying a pensioner in Edinburgh cares about poor children in the east end of London just as a pensioner in London cares about the poor children in the east end of Glasgow.

Labour, he will insist, is the only party that can lead the anti-independence campaign and it is up to it to prevent Alex Salmond and his colleagues from breaking up Britain.

His speech is also being billed as one of the most personal ever given by a British politician.

It is seen as a clear attempt by Labour high command to explain to voters who Mr Miliband is – a theme touched upon in a political broadcast last night – how he was raised and what his values are.

He will say: "My family hasn't sat under the same oak tree for the last 500 years. My parents came to Britain as immigrants, Jewish refugees from the Nazis.

"I would not be standing here today without the compassion and tolerance of our great country, Great Britain, a country that my parents saw rebuilt after the Second World War."

He will talk about his education, saying his London comprehensive was tough but orderly, and add: "I will always be grateful as I know I would not be standing here today as leader of the Labour Party without my comprehensive education."

He will also touch on other subjects as part of the conference theme of rebuilding Britain.

He will warn that Britain will not succeed if high street banks are infected by the casino culture, which caused the financial crisis, and will expand on his plan to ensure banks work together with customers and small businesses to "rebuild Britain".

However, fears by Labour insiders that Mr Miliband has not yet broken through with the British public appeared to be borne out by a poll last night, which showed only two out of 10 people thought he would make a good prime minister. This compares to four out of 10 who believe Mr Cameron is a good premier.

The Comres telephone survey of 1000 people also showed Labour trails the Conservatives on economic trust. Some 30% of people agreed that the PM and the Chancellor could be trusted to make the right economic decisions compared to 24% who believed this to be the case with Mr Miliband and Ed Balls, the Shadow Chancellor.

The poll also put Labour on 38%, down four points on last month, the Tories unchanged on 35% and the Liberal Democrats up three on 15%.