Mr Steel was an advocate of closer ties with Europe

In 1972 another prominent Labour politician, David Owen, resigned from his party's frontbench over the shadow cabinet's opposition to joining the Common Market.

The same year Jenkins resigned as Labour's deputy leader over the Common Market policy.

Four years later he was to leave Parliament to become the first British president of the European Commission.

While the Liberals maintained a consistent enthusiasm for the UK joining a federal European structure, Labour was split on the issue.

Having lost the 1979 election, the battle for control of the Labour Party saw the pro-EEC members out manoeuvred.

A new party

Right-wingers David Owen, Roy Jenkins, Shirley Williams and William Rodgers set up the Council for Social Democracy in January 1981 - originally conceived as a pressure group.

The SDP came in to being as a party in March the same year with 14 MPs - 13 defectors from Labour, one from the Tories.

Three of the gang of four that formed the SDP

An electoral pact with David Steel's Liberals was quickly established, with Roy Jenkins heading the SDP.

By 1983 Labour would enter the general election with a manifesto pledge to withdraw from the European Community.

Though there were many policy squabbles between the two Alliance parties their shared enthusiasm for Europe remained a consistent theme.

Significant electoral success would continue to elude them, however, despite the double act of the two Davids - David Owen having taken over the SDP from Jenkins.

Just after the 1987 election David Steel proposed the amalgamation of the two parties - much to David Owen's opposition.

When the parties became one Owen refused to accept the outcome opting instead to head a tiny fourth party - still called the SDP - that would fold within five years.

David Owen refused to back amalgamation

An embarrassing saga then followed while a new name was chosen for the Liberals and the bulk of the SDP.

After considerable wrangling they opted for 'Liberal Democrats' via various other guises and began afresh with their new leader - Paddy Ashdown.

Under Ashdown the enthusiasm for Europe continued unabated with support for the single currency and greater integration seeming sometimes perilously out of step with the majority view of the British public.

This concern is thought to have permeated up to the top and a brief glance at the party manifesto in recent years shows a changing stress when it came to matters European.

In 1979, 1983 and 1987 there was consistent and open support for a federal Europe - with all that implies.

Change in stress?

In Ashdown's first general election as leader, 1992, the manifesto read: "Liberal Democrats will take decisive steps towards a fully integrated, federal and democratic European Community.

"We believe that by sharing sovereignty and pooling power, Britain and its partners will be better able to achieve common goals for the economy, the environment, society and security than by acting alone."

Charles Kennedy took over from Paddy Ashdown

By contrast the 1997 manifesto said: "Being part of a successful single currency will bring low inflation and low interest rates. Staying out will result in less investment and a loss of influence."

The most recent 2001 manifesto under Charles Kennedy's leadership also stressed the benefits of joining the Euro without any overt commitment to federalism.

That said, there is little if any change in the commitment of the Lib Dems to the EU which - bar the odd dissenter - has been and remains uniformly Euro-enthusiastic.

Their support for joining the single currency remains, however, subject to a referendum - a policy they have retained since the 1990s.