The British government will unveil plans to invest £30 billion in the country\'s infrastructure in an effort to revive the stalled economy. Chancellor George Osborne will announce details of the 10-year plan in his autumn statement on the economy in the House of Commons on Tuesday. Most of the money will come from private investment from pension funds and will be used to finance the development of roads, railways and the high-speed broadband network. \"British pension funds have not been investing the savings of British people in British infrastructure. Now we are hopefully going to change that,\" Osborne told the BBC\'s The Andrew Marr Show. The chancellor has admitted that official figures would this week confirm a slowdown in the economy. He has also promised a new £40-billion scheme to help small businesses. The independent Office for Budget Responsibility (OBR) predicted in March that gross domestic product would grow by 1.7 percent in 2011, but this is expected to be sharply downgraded on Tuesday. The Bank of England estimated a figure of one percent earlier this month. \"International bodies, forecasters in the private sector, they\'re all saying the same thing, which is the British economy has slowed,\" Osborne told the BBC. To boost private sector growth, the government would underwrite bank loans to struggling small businesses worth up to £40 billion. \"The basic idea of this national loan guarantee scheme is to use the fact that the government can borrow very cheaply to help small businesses borrow money more cheaply than they do at the moment,\" Osborne said. \"The government will underwrite the loans the banks make to small businesses, in order to cut the interest rates that small businesses pay. \"That will help with their cash flow, that will help them retain their workforces, that will help them expand and invest.\" The slowdown in the economy is likely to spell bad news for the government\'s plan to eliminate the deficit in five years, although Osborne said: \"I am confident we are going to meet the targets we set out.\" He is expected to promise no let-up in his austerity drive in Tuesday\'s statement, which comes the day before unions stage a mass strike over pension reforms in a major challenge to the government. Unions say they expect up to two million people to go on strike on Wednesday against plans to raise the retirement age by up to six years to 66 and to ask public sector employees to pay up to 50 percent more in contributions. Negotiations have been going on for months and Osborne said on Sunday that the latest government offer was a \"good deal\". \"What I am trying to do is give them a good, decent pension for many, many years to come, much better than you can get if you are in the private sector these days,\" he said.