"I have heard this for the last 20 years that people, voters want to change the [two-party] system, but the two big parties like the system," Mike Hancock said.
He added that neither Conservatives nor Labour would allow their dominance on UK political arena to be challenged.
He pointed out that the minor parties, such as the Green Party, UKIP, SNP, are unlikely to bring about this change to Parliament, though have a chance to influence local governments.
Polls show a neck-and-neck race between the Conservatives and Labour ahead of Thursday's nationwide election when Britons go to the polls to elect 650 lawmakers to the House of Commons.
According to the BBC tracker that measures poll support for the parties, the Conservative Party and the Labour Party account for potential 34 and 33 percent of UK votes respectively.
