Ditching first-past-the-post system in favour of proportional representation has moved up the agenda following a high profile campaign on the issue by the Independent newspaper.

However, Hewitt conceded that reform would have disadvantages.

"I've always been in favour of electoral reform, but I'm not naïve about it," she told GMTV's Sunday Programme.

"Every voting system has its disadvantages, as well as potential advantages.

"There certainly isn't a consensus at the moment in parliament or in the government or indeed, I suspect, across the country about what the best voting system would be.

"But personally, yes, I would like to see a much fuller debate on these matters than we've had and I would hope that could actually reach some resolution on this.

"Certainly, I think we could improve on the present voting system."

Responding to the comments, Liberal Democrat deputy leader Sir Menzies Campbell said: "What we need is for those in all parties who have supported proportional representation in the past to make the case again with renewed vigour.

"The government's determination to ignore the general election result, and the increasing popular support for electoral reform are a serious indictment of their supposed radicalism."