Having to fill out a form to claim tax credits for a child conceived through rape would have "tipped me completely over the edge", a victim has said.

The UK Government has limited the number of children parents can claim tax credits for to two.

A third or subsequent child conceived through rape is exempt to the limit and tax credits can be awarded to the mother.

The applicant must fill out a form saying she was raped and provide the Department for Work and Pensions with either evidence of a conviction, evidence of an award from the Criminal Injuries Compensation Scheme or evidence from someone they have spoken to about the rape in a "professional capacity".

Scottish Labour leader Kezia Dugdale read extracts from a letter sent to her by rape victim during a Holyrood debate on the policy.

The woman warned such a form would have tipped her "over the edge" when she had to apply for support.

The anonymous victim said: "I claimed tax credits from birth to eleven months old, the hand-up I needed when I was at my most vulnerable to allow me to restabilise my family.

"Tax credits kept our heads above water, a buffer between us and the food bank, for that I am eternally grateful.

"There is no way I could complete that awful form of shame, no matter what the consequences."

She added: "Looking back, that really could have been the thing that tipped me completely over the edge, the difference between surviving to tell the tale and not."

Dugdale urged Conservative MSPs to oppose the clause.

The tax credit change was criticised by all parties inside the chamber except from the Scottish Conservatives.

The First Minister said: "No woman anywhere should have to prove that she has been raped in order to get tax credits for her child.

"I actually can't believe that in 2017 I am having to stand up in the Scottish Parliament and make that argument.

"This policy isn't just immoral, although it definitely is, it is also unworkable in practice."

Green MSP Alison Johnstone said: "Surely if you get to the stage where you are asking women to prove that the child they are claiming on behalf of is a result of rape, a single brutal attack perhaps, or conceived during an ongoing abusive coercive controlling relationship, surely you would come to the conclusion that the implications of your legislation, of the impact on the well-being, the privacy, of women and children are completely unacceptable."

The policy was labelled "abhorrent" by Scottish Liberal Democrat MSP Alex Cole-Hamilton.

Scottish Conservative leader Ruth Davidson defended the UK Government's welfare reforms.

She angered opposition MSPs by refusing to take any interventions during her speech to the chamber.

Davidson said: "There may be many who disagree with capping child tax credits at the first two childre, but not surely with such exemptions to the cap being put in place," she said.

"So, the question then comes to implementation and I am sorry to say that on this issue too many people have simply not been clear with the facts.

"I have heard members of this chamber say on television that women must complete an eight-page form in order to receive this exemption. This is simply not correct."

The Scottish Conservative leader called on the Scottish Government to use its welfare powers to alter the policy north of the border.

Davidson said: "If she (Nicola Sturgeon) chooses strong words but chooses not to act, that would indeed be shameful."

MSPs later voted 91 to 31 in favour of a Scottish Government motion, as amended by Labour and the Greens, to call on the UK Government to remove the two-child cap on tax credits and scrap the so-called rape clause.

The motion stated the Scottish Parliament is "fundamentally opposed" to the two-child limit, claiming it will push families into poverty, and "utterly condemns the disgraceful and repugnant 'rape clause"' as "unfair, unequal, morally unacceptable and deeply harmful to women and their children and a fundamental violation of women's human rights".

A Labour amendment stating the Parliament "further condemns any government that forces women to relive a horrific event in their lives to access social security", and a Green amendment condemning the cap as "yet another welfare cut that the UK Government knows will hit women hardest", were both passed by 91 votes to 31.