Four years ago, I interviewed the then education secretary and women's minister Nicky Morgan about closing the gender gap in parliament - and in particular the Conservative Party.

"I would be the first to say we need more women in politics," she told me, as we talked about the woeful under-representation of women in the Commons, especially in her own party, where women accounted for just 16% of MPs before the 2015 election.

Ms Morgan wanted to get it to 30%. "We can't go backwards," she told me.

But four years later and it seems like we are. Ms Morgan, now the culture secretary, last week became the latest in a string of talented women to quit politics. For a sitting cabinet minister to decide the cons of the job outweigh the positives is truly extraordinary.


Image: Nicky Morgan is quitting the cabinet at the height of her career

But, perhaps worn down by parliamentary gridlock overlaid with bucket loads of abuse, Ms Morgan had decided to call time on her parliamentary career at just 47.

She said: "The clear impact on my family and the other sacrifices involved in, and the abuse for, doing the job of a modern MP can only be justified if ultimately parliament does what it is supposed to do."

She is one of a number of moderate Conservative women, brought in by David Cameron on his A-list programme to diversify and modernise the party, who appear to have lost their political home under Boris Johnson's leadership against the backdrop of a toxic Brexit debate.

The roll-call of talented, ambitious women quitting the Conservative benches after being in parliament for less than a decade is alarming.

Those leaving include Amber Rudd, the former home secretary, once tipped as a possible future leader; Claire Perry, a protege of George Osborne and a former energy minister; Margot James, former digital minister and the first openly gay Conservative MP; Sarah Newton, a former minister and former deputy party chairman. Mims Davies, employment minister and Seema Kennedy, Theresa May's former parliamentary aide, are both quitting after just four years in the job.

Image: Amber Rudd was once tipped as a future Tory leader

There are others too.

Justine Greening, former education secretary - now an independent MP - is quitting, as is Dame Caroline Spelman, former environment secretary. Former health minister Ann Milton is standing as an independent candidate in her Guildford seat after losing the whip for rebelling against the government to block no-deal. Another ex-Tory, Antoinette Sandbach, is standing in her seat - but for the Lib Dems.

The group of Conservative women quitting for good might only make up nine of 19 female MPs standing down, but these are prominent women in the prime of their careers that the party can ill afford to lose. For every four men on the Tory benches, there is one woman. On the Labour benches it's a near 50-50 split.

There are some, perhaps trying to downplay the extent to which Brexit rifts and toxic abuse is polluting our political life, who want to downplay this worrying trend by pointing out that the number of women quitting is proportional to their numbers in parliament - at 30% of total retirees.

Image: Justine Greening was a rising star of the Conservative Party

But don't be fooled that this doesn't mean there isn't a problem. The make-up of those retiring typically reflects historical intakes of MPs. On that basis the percentages of women leaving should be running at 15% to 20%.

And the Tory women stepping down are on average 10 years younger and have spent a decade less in parliament than retiring male MPs, according to a report by The Guardian this week. They are quitting in the prime of their parliamentary careers and after short periods of time.

The women I talked to have a multitude of reasons to call it quits, but a common thread has been the toxicity Brexit has unleashed in our political dialogue, which has in turn been intensified by the rhetoric politicians - including the prime minister - have used.

Abuse, rape and death threats are part of everyday life and it has worn women down.

"Sexually charged rhetoric has been prevalent in the online abuse for females MPs, with threats to rape us and referring to us by our genitalia," said Dame Caroline as she announced was standing down.

"Myself, my family and my staff have borne an enormous brunt of abuse and I think quite frankly we've had enough."

The murder of Labour MP Jo Cox by a right-wing terrorist during the referendum campaign casts a long shadow over Westminster. Three years on from her tragic murder, the levels of abuse and use of violent language targeted at female MPs is having a material impact on their willingness to do these jobs.

Image: The murder of Jo Cox casts a long shadow over Westminster

I have been told that one female MP is standing down at the behest of her child, who is racked by anxiety that her mother will be harmed at work. Another MP, who said she was quitting because of intolerable levels of abuse, has been stalked by a local man who was subsequently jailed for harassment.

But it is not just the abuse that is prompting women such as Ms Morgan, Ms Rudd or Ms James to stand down. For some it is also the direction the Conservative Party is taking under Boris Johnson.

Some moderate and pro-EU MPs have found themselves politically homeless in Mr Johnson's party. This rupture was laid bare when 21 MPs were sacked for defying the whip on a no-deal Brexit, Ms Rudd and Ms James among them.

Ten since reinstated, but for some the damage done.

For Ms James, it was Brexit that broke her relationship with both her local party and the leadership. A pro-EU Tory, she says she is now out of step with the mainstream of the Conservative Party.

But she worries that the vitriol unleashed by Brexit will dissuade more women from standing, while the "macho culture" around the prime minister is a problem.

"I think the overall tenor of the government is too macho for my liking," says Ms James.

"I think there is a culture around his special advisers - or should I say his chief special adviser [Dominic Cummings] that is encouraging this.

"In the summer they set up a Brexit war cabinet and put Michael Gove in change of that. I wonder how many women are in that cabinet sub-committee, I suspect very few (the permanent four are all men, although Home Secretary Priti Patel attends frequently).

"There's no need to talk about politics in terms of war and all of this, it's just so unnecessary. It isn't a game, and it isn't a war, and we all need to dial that stuff down."

Image: Boris Johnson is overseeing a decline in the number of female Tory MPs

MPs point to the language deployed by Mr Johnson as he went to war with MPs over their determination to stop a no-deal Brexit. His repeated use of the phrase "surrender act" to refer to the Benn Act alarmed many who complained of spikes in death threats and abuse.

That the prime minister, in the chamber, dismissed such concerns as "humbug" only served to pour fuel on the fire. Many of his own MPs looked on quietly aghast. And a number of them decided to walk.

Because the sacrifices required to the do the job are no longer worth it when the environment in parliament is so toxic, colleagues are at war and nothing of substance is actually getting done.

As one woman put it to me: "More women than men asked themselves, 'Is what I am doing worthwhile, and is it worth the other sacrifices I'm asking myself and others to make?' At the moment in parliament it makes it hard to say yes."

In 2017, the year before the centenary of women getting to vote, a record number of women - 32% - entered parliament.

This was meant to be the magic "tipping point" in which women formed a big enough group within an institution to begin to shape and change its culture.

This battle was never won in the Conservative Party, where just 20% of its MPs are female. And now, there is a real risk of the party going backwards as senior Conservative women with serious ministerial and cabinet experience decide this prime minister, this parliament, this version of Brexit is not for them.

There could be a cost at the ballot box too. A poll out in late September showed Mr Johnson's popularity was falling among women, with almost half of women describing him as "dislikeable", up seven points since the end of August, and five points higher than among men.

Whatever happens in this election, women's voices cannot be allowed to be drowned out of public life because of hatred and misogyny. Ms Morgan was right, "we can't go backwards".

But the sight of such talented women quitting politics on the eve of Mr Johnson's Brexit election is a timely reminder of how much fighting we all have to continue to do.

The Brexit Election: For the fastest results service and in-depth analysis watch Sky News live from 10pm on Thursday 12 December, with a KayBurley@breakfast election special on Friday 13 December

Sky Views is a series of comment pieces by Sky News editors and correspondents, published every morning.

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