Deputy Prime Minister Nick Clegg sought on Friday to reassure his Liberal Democrat supporters that they would not be drowned out by their larger Conservative partners as Britain experiments with coalition government, according to Reuters. Clegg led his party in May into Britain's first coalition in 65 years. The government's early life has been dominated by news of drastic cuts in public spending that has put off many grassroots Lib Dems and eroded support for the party. But Clegg, keen to talk about something other than the need to cut the deficit, struck a more optimistic tone in a speech on Friday, setting out a vision of Britain in 2015 with a growing and greener economy and renewed public faith in politics. "If the coalition succeeds, by 2015 Britain will be a more liberal nation, a nation of stronger citizens living in a fairer society," Clegg said in a speech at the Demos think-tank. Opinion polls show support for the Lib Dems falling to as low as 15 percent compared with 24 percent in the May 6 election that ousted the Labour Party from office after 13 years. The left-leaning Lib Dems have only 57 seats in parliament against 305 for the Conservatives, but they obtained senior government roles as a price for joining the bigger party, which was short of an overall majority in parliament. The coalition's main goal is to virtually eliminate a record peacetime budget deficit over the five-year term of parliament and it introduced the harshest budget in a generation on June 22 to start the process. Some Lib Dem supporters fear the party is providing cover for the Conservatives during tough times and will be cast aside once a sustained recovery kicks in. Clegg said that his party was united behind the spending cuts and tax rises in the budget. "This was a coalition budget, not a Conservative budget. The Liberal Democrats stand full-square behind the budget judgment," he said. Bob Russell, a Lib Dem member of parliament who voted against plans to raise sales tax to 20 percent from 17.5 percent -- the budget's flagship measure, said he was nevertheless convinced the coalition was the best option for Britain. "While I have misgivings over VAT, I have full confidence in the coalition as being the best vehicle to take us out of the mess that Labour left us in," Russell, MP for Colchester in eastern England, told Reuters. Central to Clegg's plans for liberal reform is a referendum planned for next May on changes to the voting system to move away from the "first-past-the-post" approach that disadvantages smaller parties. That risks exposing fault lines in the coalition because the Conservatives back the existing system.