Bank of England governor Mark Carney will call for longer prison sentences for bankers who break the law in an attack on ethics in the City later.

In his Mansion House speech Mr Carney will say individuals acted with a “culture of impunity”.

But he will warn: “The age of irresponsibility is over.”

Meanwhile, Chancellor George Osborne will say he plans to bind future governments to maintaining a budget surplus when the economy is growing.

Mr Osborne will give the Mansion House audience more details of the proposal he first announced in January.

Mr Carney will say markets responsible for trillions of pounds of global trade were stained by excess, collusion and abuse and “ethical drift” had taken hold.

“Criminal sanctions should be updated, with market abuse rules similarly extended and maximum prison terms lengthened,” he will add.