They call for an immediate halt to cuts, to protect jobs in the public sector, a new round of quantitative easing to finance a "Green New Deal" to create thousands of new jobs,benefit increases to put money into the pockets of those on lower and middle incomes and give a boost to spending and a financial transaction tax to raise funds from the City to pay for investment in transport, energy and house building.
The letter headed by former European Investment Bank consultant Dr Ha-Joon Chang urges the government to engage with new ideas on stimulating growth, and warns the chancellor that his policies may push the country into further deficit rather than erase the national debt.
The paper's editorial backs up the call.
Whilst it saysvoices are not all in accord on what Plan B might constitute.
How to diversify and rebalance the economy; how to promote growth and how to restore ethics, mutualism and a sense of fair play to an economy and society does not easily command a consensus. However, we are witnessing an important shift. There is an awareness that a "business as usual" approach is no longer acceptable. The Observer welcomes this change of direction and the initiation of a debate that could prove historic in the salvaging and reshaping of our economy and the resetting of our national priorities for years to come.