Querying why only junior MPs were forced to quit Parliament over their expenses, Mr Bell added: “Neither party has yet really let go of a frontbencher.”
Last week, the Parliamentary Standards Commissioner announced he would investigate Mr Osborne after a complaint was lodged by the chairman of the Labour party in Tatton.
John Lyon said he would look into a claim Mr Osborne “claimed for mortgage payments that were not necessarily incurred, contrary to the rules of the House”.
The complainant, Laurie Burton, claimed Mr Osborne breached the MPs’ code of conduct and brought the Commons “into disrepute”. But the shadow chancellor insisted he was “relaxed” about the probe.
A spokesman said: “There was absolutely no impropriety and any suggestion of such is wrong.”
Meanwhile, Mr Bell, who stood down in 2001, is weighing up a challenge against the scandal-tainted Hazel Blears, in Salford.
