The Liberal Democrats have continued their European election campaign with a warning against adopting isolationist policies.

Charles Kennedy said that his party was committed to playing "a central role in Europe while securing change where needed".

Speaking on Tuesday, he predicted that the Lib Dems would increase their representation in the European parliament, even though the number of British MEPs is being cut as a consequence of enlargement.

He said that the cross-nation Liberal Group in the Brussels parliament holds the balance of power.

"And, as the largest national delegation in that group, British Lib Dems have been hugely influential over the past five years," Kennedy said.

"Our MEPs are dedicated to making Europe work for you. Every vote for the Liberal Democrats in the European elections is a vote to cement and enhance Britain's influence in the European Parliament.  In these elections we are standing on, and by, our record in Europe. 

"And Liberal Democrats have been using our influence in the parliament to ensure that the EU delivers practical benefits for the people of Britain."

His comments contrast with an earlier insistence that the European elections should be seen as a referendum on the government's handling of the Iraq war and its aftermath.

The Lib Dem leader accepted there were problems that need to address, such as the "inadequacies" of the Common Agricultural Policy.

But he added: "It is precisely because we are pro-European that we British Liberal Democrats can be depended upon to make a real difference in Brussels.

"We work with the system to get the best out of Brussels for Britain.  We don't just carp from the sidelines."