Ukip will be the main beneficiary if parliament does not end the perception that MPs are "splashing about on expenses" and getting drunk in taxpayer-subsidised bars, Labour's deputy leader has said.

Harriet Harman said MPs must do more to stop seeming like they are "featherbedded" as this creates cynicism and antipathy towards politics among households struggling with bills.

She said it was not good enough for MPs to say "we are better than we were" after the 2009 expenses scandal, and called for further progress to be made on changing the "gentleman's club" culture of the Commons.

Harman made the comments after a week in which the culture secretary, Maria Miller, resigned over her expenses, the Nigel Evans case exposed a hard-drinking culture in Westminster and a Channel 4 survey found that a third of parliamentary staff have experienced sexual harassment.

Speaking on Sky News's Murnaghan programme on Sunday, Harman said: "When people are struggling in their lives, it's the idea that we're splashing about on expenses. When we're making the laws that govern other people's behaviour and we don't seem to be able to behave ourselves. That's why we need to put ourselves in order."

She also said a drinking culture in parliament, which is subsidised by the taxpayer, was not good for MPs or the way the public perceive them.

"It's partly a legacy of the idea that MPs were around late at night and a lot's been done on the hours. When I first arrived it was absolutely ridiculous … It was a real problem and some people, really good MPs, came down to the House of Commons and found that their lives then fell on the rocks of being in the bar so it didn't do the MPs any favours either.

"So I do think treating it as a proper place of work, having proper hours and not having it as a kind of sort of gentleman's club where a lot of people were doing their work during the day in the law courts as barristers or in the City as financiers and then they'd come along to what was a gentleman's club of the House of Commons for a bit of legislating and a spot of dinner. I mean, that was all ridiculous and that has changed very, very much but I think there's still further to go."

A ComRes survey for the Sunday Mirror and Independent on Sunday showed Ukip scoring one of its highest ever poll ratings at 20% in a bounce attributed to recent Westminster scandals while an Observer/Opinium poll put the party on 18%.

Bob Stewart, a Tory backbencher, said it was unfair when Ukip politicians were not better behaved than MPs. "The public actually believe Ukip are not like the rest of us. Of course they are. And actually they're worse," he said.

All political parties are under pressure to clean up their act after a series of exposes about bad behaviour by MPs. John Bercow, the Speaker, has demanded action from the whips' offices and there has been speculation that he could move to end the taxpayer subsidy for parliament's bars.

The Conservatives have introduced a new code of conduct to protect staff against bullying and harassment by MPs. But the code has been criticised for being voluntary. Labour has also reviewed its complaints procedures and the Liberal Democrats have appointed a pastoral care officer in the wake of allegations that its former chief executive Lord Rennard inappropriately touched female party activists.

Over the weekend, a former senior Tory official was accused of holding a sex party at the Conservative party conference in 2011, inviting people to a taxpayer-funded suite using the networking app Grindr, which is geared towards gay, bisexual, and bi-curious men. The parliamentary expenses watchdog is looking into whether allowances could have been misused, although his Conservative bosses told the Guardian there were no complaints against him after he was disciplined over this incident.

Concerns about booze-fuelled behaviour in the Commons have come to light following the trial of Evans, who was last week cleared of a string of sex offences. During the trial, the former deputy speaker's defence counsel admitted he had made inappropriate passes at Westminster workers and engaged in "drunken over-familiarity" with Commons staff.

In his first interviews since he was cleared of rape and sexual assault, Evans told the Mail on Sunday he was only drunk around Westminster from "time to time" and was not "plastered every night as was claimed".

The Tory MP also revealed he had considered killing himself during the 11-month ordeal between being arrested and charged. Evans is to campaign for the Crown Prosecution Service to pay back his £130,000 in legal expenses, amid questions about why the case was ever brought in the first place.