The chancellor should take action to ensure Britain can join the euro, the Liberal Democrats have said.

Rather than wait for convergence of the British and European economies, Gordon Brown should take steps towards UK entry to the eurozone, the party's Treasury spokesman, Matthew Taylor, said on Tuesday.

Speaking at the launch of a Centre for Reform pamphlet listing the benefits of the euro, Taylor criticised Brown for delaying action on adopting the currency.

"The chancellor's approach to the euro has been simply to wait for the lucky chance of convergence," he argued.

"In truth that has always been a policy for delay. Every single member of the eurozone actively steered their economy to meet the conditions they believed necessary for them to make euro membership possible - it didn't happen by chance.

"The government needs to have the courage and the conviction to make its decision to join, and prepare the economy for it.

"Otherwise, quite correctly, nobody will believe Britain is serious about joining the euro."

Simon Buckby, campaign director of the pro-euro Britain in Europe group, has warned that the organisation faces the prospect of mass resignations if a date for the referendum on the issue is delayed further.

"Britain's isolation from the euro is costing us dear," he said. "We are losing trade, investment and therefore jobs because we are out.

"Our isolation from the euro is also giving heart to anti-Europeans who want to get Britain out of the EU altogether."