Public respect for MPs has never "really recovered" since the expenses scandal, according to Martin Bell.
The anti-sleaze campaigner and former independent MP for Tatton appeared on the breakfast show on the tenth anniversary of the scandal, in which it emerged MPs were claiming for things like moat cleaning, duck housing and even mortgage fraud.
"It changed our pereception of MPs. They were formerly held with a measure of respect and that all dissolved with the scandal," Mr Bell told talkRADIO's Julia Hartley-Brewer.
"I honestly don't think they have really recovered it."
Mr Bell claimed the scandal had helped keep MPs "honest" to date, but suggested a "sense of entitlement" among politicians could lead to a repeat.
And a recent investigation by the Telegraph found that there had been 377 suspensions of MPs' credit cards since the 2015 election, because they had broken expenses rules.
"It is sort of creeping back, the scale of expenses seems to be rising," Mr Bell said.
"What I think happens - and I saw it myself in my four years in the Commons - you develop a sense of entitlement. You have been elected by your constituents, people call you honourable, and you might even start to believe it then think you're entitled to live on a somewhat lavish scale."
He added: "Being an MP is a privilege and you are not in there to enrich yourself. You are there to serve the people who elected you."