After the UK election outcome shocked the world, Theresa May announced that she will form a coalition government with Northern Ireland's Democratic Unionist Party (DUP), describing the 10 newly-elected MPs as her "friends and allies".

The socially conservative party strongly opposes same-sex marriage and extending abortion rights. DUP MPs are in favour of leaving the European Union, but want a soft Brexit, which they are likely to demand in return for their support in propping up the Tories.

Theresa May's new allies have frequently courted controversy with their views on climate change, LGBT rights, abortion and the death penalty.

Here are some of their staunchest policies.

Anti-abortion stance

DUP leader Arlene Foster has vowed to prevent the Abortion Act 1967, which established legal abortion in the UK, from becoming law in Northern Ireland.

"I would not want abortion to be as freely available here as it is in England and don't support the extension of the 1967 act," Foster told The Guardian last year.

Access to abortion services in Northern Ireland is only permitted if a woman's life is at risk or if there is a permanent or serious risk to her health. It is illegal for a woman to have an abortion in the cases of rape, incest or fatal foetal abnormalities.

Public opinion in Northern Ireland is in favour of a major overhaul to the abortion law. According to a 2016 poll of 1,000 people conducted by Amnesty International, 72% of people support the legalisation of abortion in the cases of rape, incest and when the foetus will not survive outside the womb.

Amnesty poll Northern Ireland abortion law
75% of Irish public support the legalisation of abortion in the cases of rape and incest and when the foetus will not survive outside the womb Amnesty International

Opposition to same-sex marriage

Northern Ireland is the only part of the UK where same sex marriage is not legal. The DUP used a controversial veto mechanism to block gay marriage legislation. DUP MPs have made shocking comments about the LGBT community in the past, describing gay people as "disgusting" and "an abomination".

Foster has defended her party's opposition to same-sex marriage by insisting that many gay people do not want to get married.

"This suggestion that every single person who's a homosexual wants to change the definition of marriage is actually wrong," she told the BBC.

"I know plenty of people in that community who don't want to see marriage redefined and are quite content to live in partnership," she said.

Climate change denial

The party previously appointed climate change denier Sammy Wilson as its environment minister. He has called climate change a "con" which "green lefties are hysterical about" and described the Paris climate accord as "a delusion... a piece of window dressing for climate chancers who wished to pretend that they were doing something about an issue which they can't affect anyhow".

People have expressed concern about May's alliance with a party espousing such views.

"The DUP is stuffed with climate change deniers, homophobes and misogynists. May's alliance is a dishonourable coalition of chaos," environmentalist George Monbiot tweeted.

Renewable Heat Incentive scandal

Foster was embroiled in the Renewable Heat Incentive (RHI) scandal while she was Northern Ireland's enterprise minister.

The scheme aimed to increase consumption of heat from renewable sources, but ended up costing the public purse almost £500m.

When she became first minister of Northern Ireland, Foster refused to stand aside and denied culpability. The botched scheme forced deputy minister Martin McGuinness to resign and led to a snap election in March.

Arlene Foster Theresa May
Prime Minister Theresa May has said she will form an informal coalition with Northern Ireland's Democratic Unionist Party (DUP) led by Arlene Foster Charles McQuillan/Getty

Support for the death penalty

In 2011, five DUP MPs called for the death penalty to be reinstated. They said that many horrific crimes throughout the UK had led many to question whether there are certain criminals whose crimes demand such a sentence.

"With victims' families having called for the death sentence as an appropriate punishment, we should be turning our minds to whether our justice system deals appropriately with certain criminals," they said.

Creationist views

Several of the DUP's senior members are creationists who have called for the national curriculum to be based on the Bible.

Thomas Buchanan, a DUP assembly member for West Tyrone, endorsed a school event promoting creationism and "the biblical case for the sound teaching of children." The event focused on how "to counter evolutionary teaching".