On 10 December 1997, prime minister Tony Blair faced the first significant parliamentary rebellion of his premiership as the House of Commons voted to cut benefits for lone parents. Despite the government securing the passage of the Social Security Bill, 47 Labour MPs defied a three-line whip to vote against the measure. On top of this, an estimated 100 Labour MPs abstained.

***

The revolt was sparked by the government’s decision to implement a policy originally devised by the previous Conservative administration. In the 1996 budget, the then chancellor, Kenneth Clarke, announced the abolition of the lone parent premium and one parent benefit, arguing that the only substantial extra expense for single parents was childcare.

Clarke unveiled his plan to “align the benefits paid to lone parents and couples with children, because both care for children.”

The proposal would leave new claimants approximately £6 a week worse off.

In opposition, Labour had vehemently opposed these proposals. Harriet Harman, speaking as shadow social security secretary, insisted that the way to get lone mothers out of poverty was “not by cutting the amount on which they have to live year by year and plunging them further into poverty.”

In government, however, Blair was bound to his pre-election pledge to match the previous government’s spending limits for the first two years. Harman, now the secretary of state for social security, was tasked with steering the lone parent benefit cuts through parliament.

The build up to the debate on 10 December pointed to significant political showdown within the Labour Party. By November, more than 80 MPs, including 17 Liberal Democrats, had signed a commons motion opposing the planned cuts.

***

Speaking in the commons, Harman argued the government was offering a “new deal” that prioritised work over welfare. “Our aim is to give lone parents the opportunities that previously they have not had”, Harman said.

“We are offering lone parents a new deal and providing them with what they want, which is the opportunity to work instead of a life devoid of any choice except dependence on benefits.”

Audrey Wise, the MP for Preston, accused the government of “taking fat off [lone parents] without finding out whether they are already anorexic.”

Wise added: “I think we are entitled to say that these measures are not in accord with Labour values.

“They are not economically necessary, they will not lead to good economic results and they are disastrous as instruments of social policy.”

Ken Livingstone, a leading leftwinger, said the chancellor’s justifications resembled “a used-car salesman drawing attention to the small print”. He warned that the policy was a performative act of cruelty that was “about demonstrating to the international markets that we can be as brutal to the poor as the government we replaced”.

Tony Benn contrasted the measure with the 1945 Labour government, which had tripled the “widow’s pension from 10 shillings a week to 26 shillings a week”.

The veteran Labour MP stated: “I must say, very respectfully, that the government have not taken a hard decision; they have taken the easiest decision possible, hammering the poorest people who have no bargaining power…

“We are going back to the Victorian concept of the deserving poor, who want work, and the undeserving poor, who prefer to look after their children.”

Alan Simpson attacked the “shabby myths” used to justify the bill, declaring: “It is not a hard choice to pick on the weakest in the playground and kick buckets out of them.”

Alex Salmond, the leader of the Scottish National Party (SNP), said that the debate could amount to “Labour’s Black Wednesday”.

He said: “I wonder, when we look back on today’s proceedings, whether they might not be seen as New Labour’s Black Wednesday, which destroyed the social credibility of the new Labour government.”

Peter Snape, who vowed to vote for the bill, warned the rebels that the newspaper headlines the next day would depict “an ashen-faced Tony Blair… contemplating the smoking wreckage of his party”.

Snape insisted that he “heaved a sigh of relief” when he heard the commitment to adhere to the last government’s spending limits. He said the pledged neutralised “the central weapon in the Conservatives’ armoury, which they used to cheat their way to power in 1987 and 1992 – saying that voting Labour would mean tax increases”.

He added: “Having made our bed, we shall have to sleep in it”.

Clive Soley, the chair of the Parliamentary Labour Party (PLP), urged MPs to see the “wider context” and not to derail the government’s agenda. “We are at the beginning of a project that will be radical and long remembered”, he said.

“Do not lose sight of the long-term aim. Keep your heads and be sensible tonight and on every other occasion.”

The Conservatives, led by William Hague, supported the government in its attempts to enact the cuts it first announced in 1996. But the party sought to exploit the Labour rebellion. Speaking at prime minister’s questions, Hague said Labour MPs would be “dragged through the lobby to vote for a measure which before the election it called shameful, malign and completely wrong”.

He added: “Is that not another example of a government without principles and without values?”

Blair responded: “There are different priorities, but we believe that the most important thing is to help lone parents off benefit and into work, and to do so in a way that does not lose control of public finances.”

Iain Duncan Smith, the shadow social security secretary, dubbed the legislation the “Peter Lilley Memorial Bill” – after the former Conservative social security secretary.

At the bill’s report stage, 47 Labour MPs voted for a Liberal Democrat amendment to block the cuts, with over 100 abstentions. The amendment was nonetheless defeated by 457 votes to 107.

***

The bill secured its third reading by 295 votes to 58. Only five Labour MPs – Tony Benn, Jeremy Corbyn, Bernie Grant, John McDonnell and Dennis Skinner – voted against the bill at third reading.

The bill passed its commons stages, therefore. But the surrounding debate exacted a heavy political toll.

On the day of the vote, Malcolm Chisholm, a junior minister at the Scottish Office, had resigned from the government, stating he could not “bring myself to vote with the government tonight.”

Three parliamentary private secretaries also resigned from their positions, namely Michael Clapham, Gordon Prentice, and Neil Gerrard. Alice Mahon, an aide to culture secretary Chris Smith, had to be sacked after she refused to support the bill.

Gerrard had told the commons: “I cannot in all conscience support one of the clauses of the bill – the clause that cuts single-parent benefits.”

Mahon told BBC News: “I was sacked. I have no regrets. I’m devastated that I had to vote against a Labour government. There is no triumphalism in this at all. I feel very emotional and upset.”

Blair, however, stood his ground.

He responded: “We will do [benefit reform] fairly and sensitively, but we are going to stand absolutely, resolutely firm on change because the welfare system isn’t working and it needs reforming.”

Alastair Campbell, the Downing Street director of communications, recorded in his diary that Blair believed “All we can get out of this is strength”. The government’s stance, he said, aimed to signal that “the bloke is not for turning.”

In the aftermath, chief whip Nick Brown reportedly began a series of disciplinary interviews.

The rebellion also implicated senior cabinet figures. Reporting suggested that cabinet ministers David Blunkett, John Prescott, Robin Cook, Frank Dobson and Clare Short harboured doubts about the direction of welfare reform.

According to a leaked memo, Blunkett reportedly feared the cuts would make a “mockery of our professions on a social exclusion and the construction of a more just society”. Prescott was forced to deny reports that he had called Harman a “liability” and asked for her to be sacked.

The policy badly damaged Harman’s standing. She was sacked from the cabinet in July 1998.

In her memoirs, Harman later admitted that there “was no argument in favour” of the cuts and pointed to pressure from the Treasury. “I didn’t feel able to second-guess [Gordon Brown] on what the money markets would do”, she wrote.