By Peter Griffiths
BRIGHTON, England (Reuters) - Britain's Labour leader Ed Miliband will stake his claim to replace Prime Minister David Cameron at the 2015 election on Tuesday with an attack on government cuts that he blames for the longest fall in living standards in more than a century.
Miliband will try to improve his disastrous personal poll ratings and convince voters they can trust his opposition party with the economy, accusing Cameron of delaying the recovery from its worst crisis since World War Two.
In a speech to Labour's annual conference, Miliband will cast Cameron's Conservatives as the party of the rich and say only Labour will help families and small businesses bruised by years of stagnation, public cuts and weak wage growth.
Miliband, who beat his older brother to the leadership in 2010, hopes to silence party critics who want him to give a clearer message and do more to be seen as a future premier.
"We have the slowest recovery in 100 years, 1 million young people looking for work ... the longest fall in living standards since 1870," he will say. "You've made the sacrifices, but you've not got the rewards."
Center-left Labour, which has a narrow lead over the center-right Conservatives, lost power in 2010 after its second worst election defeat since 1918. The perception of Miliband is worse.
A poll by research company YouGov this month suggested only 3 percent of voters saw Miliband as a natural leader, compared to 14 percent for Cameron, who was also seen as stronger, more decisive and better in a crisis.
If Labour wins the election, one of its first acts will be to stop a planned cut in the rate of corporation tax and use the money to help small companies, he will say.
In words that echo former U.S. president Ronald Reagan's phrase in his 1980 White House campaign, Miliband will ask voters "are you better off now than you were five years ago?".
Labour's economic reputation was shredded by the financial crisis and a period of borrowing and spending that led to a record peacetime budget deficit before their defeat.
Labour says it will have "iron discipline". Finance chief Ed Balls cast doubt on a planned 50 billion pound ($80.16 billion) fast rail link between London and the north on Monday, saying it might be scrapped if costs rise.
Miliband will announce plans to build 1 million new houses by 2020 and offer more free childcare to families squeezed by what he calls a "cost of living crisis".
The Conservatives dismissed the plans as "economic incompetence", while the Institute of Directors, a business lobby group, said Miliband was "tinkering at the edges".
Miliband, 43, whose Marxist father escaped the Nazis in Belgium by catching one of the last boats to Britain in 1940, is trying to restore economic credibility and lift his personal ratings at Labour's meeting in Brighton, southern England.
Supporters say he is a strong figure who united his party after years of feuding, blocked Cameron's support for military action in Syria and had the courage to stand up to media chiefs such as Rupert Murdoch.
Detractors, however, dismiss him as "Red Ed", a left-wing figure who lacks gravitas, struggles to convey his beliefs and whose style alienates voters.
Miliband's message was obscured by coverage of a former Labour adviser's memoirs that reopened old party feuds and exposed evidence of deceit and spin in its media operation.
One of Miliband's biggest obstacles is the message from opinion polls that voters have more faith in the Conservatives to run the world's sixth biggest economy.
Signs of a surprisingly strong recovery have allowed the government to say it has won the argument about how to secure the recovery.
Conservative Business Minister Matthew Hancock said the corporation tax move would cost jobs and the housing plan would lead to more public borrowing.
"This is yet more economic incompetence," he said. "Tax rises on businesses and the same old Labour policy of more borrowing and more debt would undermine the recovery."
($1 = 0.6237 British pounds)
(Editing by Alison Williams)