More than 70 MPs have written to the Prime Minister urging her to immediately ratify the Istanbul Convention which aims to end violence against women.

It comes as the Commons debated a motion marking the UN International Day For The Elimination Of Violence Against Women.

The letter, organised by Labour MP Seema Malhotra who also led the debate, said "words are not enough" and urged Theresa May to immediately act to try to end the abuse.

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The MPs warn that violence against women has "increased rapidly" in recent years but services are struggling to cope and victims are "being turned away at the door".

It accuses ministers of "failing to deliver" on Mrs May's promise to tackle the problem and said the convention should be ratified "without further delay".

Ms Malhotra (Feltham and Heston) told the Commons that domestic violence ruins lives and costs the public billions of pounds a year.

She said: "The scourge is present in every community across our nation. Domestic and sexual violence know no boundaries in terms of age, geography, ethnicity or social background."

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Many women who suffer abuse are further tormented online, and websites such as Facebook and Twitter need to take more responsibility for cracking down on it, she said.

And she said there is an "urgent need" for compulsory sex and relationship education.

Conservative MP Maria Miller, who chairs the women and equalities select committee, praised Mrs May for the leadership she showed as home secretary in tackling gender-based violence and discrimination.

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She brought in new laws against coercive control, modern slavery and rules around the reporting of female genital mutilation (FGM).

But Mrs Miller said more can be done to tackle online abuse.

She said: "It's right that we look out to the world, but we also have to look to our own back doorstep as well.

"I think the biggest challenge in our lives is the way we tackle the online world, and this is something we need to do more about."

Conservative MP Alex Chalk (Cheltenham) called for longer jail sentences for the most serious stalkers.

It comes after Home Secretary Amber Rudd announced this week that stalkers will be hit with Asbo-style bans and will face up to five years in jail if they breach them.

Mr Chalk said: "For those most serious cases where the victims' lives are made a living hell, where they live in constant fear, we need to give the courts the powers they need to protect victims.

"And that means treating stalking as a serious crime, not a minor offence.

"Because the reality is that where a stalker pleads guilty for the most serious imaginable offence, and that could by the way be a repeat offence, the maximum he, and it's usually a he, can end up serving is just 20 months."

He said judges have complained they do not have the sentencing powers to imprison certain dangerous stalkers for long enough.

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SNP social justice spokeswoman Eilidh Whitford said she has put forward a Private Members Bill that would require the Government to publish a timetable towards ratifying the Istanbul Convention.

She told MPs: "The process has stalled and the Istanbul Convention has now been languishing on the backburner for four-and-a-half years. My Bill is simply an attempt to shift that logjam."

Shadow Foreign Office minister Liz McInnes said new technology had had "a detrimental effect" on women, pointing to the online abuse suffered by fellow MPs Anna Soubry, Luciana Berger and Jess Phillips.

"The internet, and in particular social media, has fuelled gender violence," she said,

"The tone online in the UK is becoming more and more vitriolic, and threatening towards women."

She also hit out at the practice of female genital mutilation (FGM), which has been suffered by around 200 million girls worldwide.

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Ms McInnes also told MPs she had been contacted by church groups looking to protect girls living in Britain from being returned to their home country for FGM.

Tory MP Rebecca Pow (Taunton Deane), meanwhile, praised a recent storyline in BBC Radio 4's The Archers for raising awareness of domestic violence.

She said: "I am a great Archers fan, and I do think the storyline in the Archers really has helped raise awareness of this area.

"It's something, personally, I wasn't really aware of, and it was utterly shocking. I really think this has brought it to the fore."