There have been four such arrangements, and one alleged proposal, at the national level. In many local councils in the UK there are similar arrangements, although there are also arrangements where the Lib Dems and Labour oppose each other and instead form a local alliance with another party or with independent councillors.
Before the Labour Party had been formed, various candidates stood for Parliament with backing of the Liberal Party and the Labour Representation League, including Thomas Burt, Harry Broadhurst and Alexander Macdonald. These MPs were referred to as 'Lib–Lab', although there was not a formal 'pact'.
In 1903 an agreement was made between Herbert Gladstone (then Chief Whip of the Liberal Party) and Ramsay MacDonald (Secretary of the Labour Representation Committee) that, in thirty constituencies, the Labour Party and the Liberal Party would not stand against each other, and thus risk splitting their vote. As a result of this agreement, in contests against the Conservative party, 29 Labour MPs were returned at the general election of 1906.
In the 1923 general election, both parties campaigned on the issue of free trade. The Conservatives, who had campaigned to introduce protective tariffs, lost their parliamentary majority but remained the largest party. The Liberals agreed to enable the formation of the first Labour government in 1924 under Ramsay MacDonald.
In the 1929 general election, Labour won the greatest number of seats, though not a parliamentary majority. The now much weakened Liberals allowed the formation of the second Labour government by not allying with the Conservatives to defeat the new government.
In March 1977 the Labour Government, left with no overall majority following a by-election defeat, faced a motion of no confidence. In order to remain in office, Prime Minister James Callaghan approached the Liberal Party under the leadership of David Steel. Callaghan had been prime minister for just one year, having succeeded Harold Wilson who had led Labour to a three-seat majority in October 1974.
An agreement was negotiated, under the terms of which the Labour Party accepted a limited number of Liberal Party policy proposals and in exchange, the Liberal Party agreed to vote with the government in any subsequent motion of no confidence. While this 'pact' was the only official bi-party agreement since the Second World War (until the Conservative–Lib Dem coalition following the 2010 election), it fell far short of a coalition. The Lib–Lab Pact's end was confirmed on 7 September 1978, by which time Callaghan was expected to call a general election, but instead he decided to continue as leader of a minority government until May 1979, when after a vote of no confidence it was forced to hold a general election, in which Margaret Thatcher led the Conservatives back into power.
Proposed coalition of 1997
In the lead up to the 1997 general election, a coalition government was discussed by Tony Blair and the Lib Dems, according to Paddy Ashdown's The Ashdown Diaries. Ashdown, a strong proponent of a Lib-Lab coalition, said that from Blair's point of view, in order to get the Conservatives out of power and because he wanted to move his party towards the New Labour ideal, a coalition would strengthen his majority in the likely event of a victory. To get the Liberal Democrats into his Cabinet, he allegedly agreed on their terms of electoral reform. Tony Blair was still considering attempting to form a coalition government with the Liberal Democrats on the day of the general election, until the full scale of his Labour Party's majority became clear. It is alleged that Blair still harboured thoughts of getting the Lib Dems into Cabinet, but that John Prescott's resignation threat stemmed this.
Proposed coalition of 2010
After the hung parliament in 2010, the Liberal Democrats, as they had indicated they would do so prior to the election, first began negotiations with the Conservatives – as the party which won the most votes and seats – about the possibility of forming a government; but, after talks appeared to have stalled, complementary negotiations were undertaken with Labour.
Labour's delegation for negotiations included Peter Mandelson, Andrew Adonis, Ed Miliband, and Ed Balls. Press rumours of a possible Lib Dem-Labour deal were publicised, with Gordon Brown alleged to be willing to offer a referendum on the alternative vote system if an arrangement which would have kept him in government could be agreed.
A Lib-Lab coalition would, however, have been eight seats short of a majority. A coalition of Labour, the Liberal Democrats, the SDLP, the Alliance Party of Northern Ireland and the Green Party – a "rainbow" or "traffic light" coalition – would have therefore been needed to give even the smallest possible majority. For this, amongst other reasons, the talks failed. On the collapse of talks with Labour, a deal between the Liberal Democrats and Conservatives was reached (subsequently being approved by Liberal Democrats members at a special party conference).
There was a significant level of hostility to such a deal within the Labour party with coalition proposals being opposed by, among others, former cabinet ministers John Reid, Alan Johnson, David Blunkett and former leader Neil Kinnock. John Reid said that such a coalition would be "bad for the country".
David Laws, chief negotiator for the Liberal Democrats in coalition negotiations, subsequently commented on Labour's preparation and conduct in negotiations - his main areas of criticism centred on Labour's lack of contrition about their record over the previous 13 years, inadequate preparation for discussions, their unwillingness to accommodate Liberal Democrat policy proposals in the potential programme for government, and the arrogant and patronising attitude of specific key Labour figures. Specifically he said that whilst Gordon Brown was quite serious about pursuing talks, he accused former minister Ed Balls of "sabotaging" the talks.
Possible coalition after 2015 general election
The party which wins the most seats but fails to get an absolute majority in the house has the right to attempt to form a government first, either on their own or in a coalition, Nick Clegg stated prior to the 2010 election. He stated his willingness to work with the Labour party if they won a plurality of the votes in 2015. However, some reports said it was unlikely that this would happen under the leadership of Nick Clegg, as both Ed Miliband and Ed Balls voiced discontent with Nick Clegg over his partnership with David Cameron. Later reports indicated that Miliband and Balls were more relaxed with the thought of a Lib-Lab government after the 2015 election. According to an article in The Daily Telegraph, a shadow Cabinet minister, who was close to Mr Miliband, said: “Our activists really hate Clegg. But if having him as Deputy Prime Minister was the price of getting Ed into Number 10 then they would have to stick it.” For years, Miliband is said to have refused to speak to Clegg, although relations thawed as the 2015 election grew closer. “The contact is there and the leaders' offices are now in touch,” a senior party figure said. Senior members of Miliband’s team, including Lord Adonis, the former Cabinet minister, had been urging him privately to prepare for fresh coalition negotiations after the 2015 election because opinion polls suggested no party would win an outright majority in 2015.
However, neither a coalition nor a pact between the Liberal Democrats and the Labour Party was necessary, following the surprise victory of the Conservatives in the 2015 General Election and the loss of 49 Liberal Democrat seats. 
National Assembly for Wales
When the first elections to the new Welsh Assembly took place in 1999 no one party had an absolute majority, and initially Labour sought to run a minority administration. Following a series of close votes and much criticism of the weakness of the Assembly administration, Labour and the Liberal Democrats formed a coalition in October 2000 with the two parties sharing power, including ministerial appointments, with Labour the majority party. The agreement ended at the elections of 2003 when Labour won 50% of the seats and decided to form a minority government.
After the first general election to the reconvened Scottish Parliament in 1999, the Scottish Liberal Democrats signed up to what was termed a "partnership government" with Labour, with both parties providing ministers in a shared government.
Although standing on separate manifestos in the succeeding Scottish Parliament general election, 2003 the joint working continued, with Labour's Jack McConnell serving as First Minister, and the Lib Dems' Jim Wallace serving under him as Deputy First Minister (and Minister for Enterprise and Lifelong Learning) who was then succeeded by Nicol Stephen of the same party as Deputy First Minister.
The Scottish Parliament general election, 2007 saw the Scottish National Party (SNP) surpass Labour as the largest party by one seat. The Scottish Liberal Democrats decided against coalition with either the SNP or Labour, and abstained in the vote for First Minister, won by SNP leader Alex Salmond.
Whilst not a pact, ahead of the 1997 election Labour Leader Tony Blair and Lib Dem leader Paddy Ashdown set up the Labour-Liberal Democrat joint committee on constitutional reform to discuss devolution in Wales and Scotland, and led to Prime Minister Tony Blair setting up a joint Lib–Lab cabinet committee. In part this led to the Scottish and Welsh alliances noted above. The committee was disbanded by Tony Blair and Charles Kennedy in September 2001.
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