That's completely untrue. Even if you accepted Osborne's argument, there's the question of whether to cut spending or raise taxes.
But the fact is, there are two effective ways to deal with the debt: growth and inflation. Osborne's policies have delivered neither. We should have accepted a short term growth in debt in order to secure the recovery and then used that growth to eventually reduce and eliminate the deficit. Osborne set out to eliminate the deficit in a single parliament, he has failed miserably. Part of the reason for that is that his policies and approach killed the growth in the economy and the insecure, low-paid jobs that have been created don't deliver much in the way of tax revenue so tax receipts are below his predictions.
Britain didn't need austerity, there was no pressing crisis that needed it, instead Osborne chose it and as a result the country is a lot worse off.