Labour should not be afraid to talk about England's national identity, Ed Miliband has said, but he rejected calls for an English Parliament.
The Labour leader said "Englishness" had been overlooked in the debate about Scottish independence.
Expressing national identity should strengthen the case for the UK not undermine it, he argued.
His speech was dismissed by Plaid Cymru as "vacuous" and English Parliament campaigners said it was "disingenuous".
In his most direct attempt since becoming opposition leader to address the future of the UK - and drawing heavily on his own family history - Mr Miliband said those seeking to break up the Union were offering a "false choice" and a "narrow view" of national identity.
Describing himself as the son of a Jewish refugee, who grew up in London but spent time in Yorkshire and is an MP there, Mr Miliband said Britain should be a country "where it is always possible to have more than one identity". People should not have to choose between being British, English, Scottish or Welsh, he said.
The Cross of St George had been reclaimed from the BNP, he said, and he "applauds" people who flew it, adding: "Now more than ever, as we make the case for the United Kingdom throughout the United Kingdom, we must talk about England."
He also took a swipe at Top Gear presenter Jeremy Clarkson, who said in a recent newspaper column that breaking up the Union "would be as sad as waving goodbye to a much loved, if slightly violent, family pet".
Mr Miliband said: "In Scotland, the narrow nationalists of the SNP pose a false choice. They ask: are you Scottish or British? I say you can be both.
"And here in England there are people like Jeremy Clarkson who shrug their shoulders at the prospect of the break-up of the Union.
"A narrow view of identity would mean concern for the young unemployed in Scotland does not reach Newcastle or that we in England would care less for the pensioner in Edinburgh. What a deeply pessimistic vision.
"It's a mistake wherever you find it. Having to say: Scottish or British, Welsh or British, English or British. I don't accept any of that. It's always a false choice."
Mr Miliband acknowledged the influence on his thinking of his new policy chief Jon Cruddas, the Dagenham and Rainham MP who was at the forefront of a campaign to beat the BNP in East London and has called on Labour to reconnect with its English working class roots.
But instead of setting up an English Parliament, which would involve "more politicians", extra powers should be devolved to English local authorities, argued the Labour leader.
Quizzed afterwards about why he did not support an English Parliament, Mr Miliband said: "I don't detect the demand that there was in Scotland, for a Scottish Parliament, in England. I don't feel that. I feel like people want an appreciation and a recognition of English identity."
'Partnership of equals'
An ICM opinion poll for the Daily Telegraph in January suggested 40% of Scots backed independence, while 49% of English people favoured an English Parliament.
English voters - who would not get a vote in a referendum - were also more keen on Scottish independence than Scots, with 43% supporting full independence.
Peter Davies, mayor of Doncaster, who campaigns for an English Parliament and counts Mr Miliband among his local MPs, said Labour had already broken up the United Kingdom and it was "unfair" that people living in England had to "subsidise" those in Scotland and Wales.
"It is not just Jeremy Clarkson who has shrugged his shoulders at the break up of the Union, it has been the Labour Party for the past 20 years, and the entire political elite," said Mr Davies, who is a member of the English Democrats.
He accused Mr Miliband of being "disingenuous" and said the real reason he opposed an English Parliament was that the "Labour Party would not be able to control it".
The SNP said Mr Miliband's speech showed "how out of touch he is with Scotland".
Humza Yousaf, the party's MSP for Glasgow, said: "The fact is, the current UK constitutional arrangements are unsuitable for Scotland, and unfair for England.
"What Mr Miliband desires for England can only be delivered by Scottish independence, giving both nations a new relationship based around a partnership of equals, bound by a social union of our shared history and culture."
Welsh nationalists Plaid Cymru, which backs an English Parliament, branded Mr Miliband's speech "vacuous and lacking in substance".
Supporters of Scottish independence, led by First Minister Alex Salmond, launched their campaign last month for a yes vote in a referendum due in 2014, saying Scotland would be "greener, fairer and more prosperous" as a result.
Labour, the Conservatives and the Liberal Democrats all oppose such a move, saying the UK will always be stronger as the sum of its constituent parts. The three main parties also reject a separate English Parliament.
Prime Minister David Cameron has vowed to campaign strongly for Scotland to stay within the Union. In a speech last year, he was criticised for calling for an end to "state multiculturalism" and arguing the UK needed a stronger national identity to stop people turning to extremism.