The party manifestos published before the June 2017 General Election made the following references to issues related to international Freedom of Religion or Belief
Conservative Party: We will expand our global efforts to combat extremism, terror, and the perpetration of violence against people because of their faith, gender or sexuality’.
Labour Party: We will appoint dedicated global ambassadors for women’s rights, LGBT rights and religious freedom to lead the government’s work to fight discrimination and promote equality globally – working alongside a Labour government’s Minister for Peace and Disarmament
Liberal Democrats: We will appoint an ambassador-level champion for freedom of belief to drive British diplomatic efforts in this field, and campaign for the abolition of blasphemy, sedition, apostasy and criminal libel laws worldwide, having already been responsible for ending them in this country.
And here is what the parties that mentioned Freedom of Religion or Belief said in their official manifestos before the 2015 election:
Conservative Party: We will stand up for the freedom of people of all religions – and non-religious people – to practise their beliefs in peace and safety, for example by supporting persecuted Christians in the Middle East.
Labour Party: We will appoint a Global Envoy for Religious Freedom, and establish a multi-faith advisory council on religious freedom within the Foreign and Commonwealth Office.
Liberal Democrats: We will appoint an Ambassador-level Champion for Freedom of Belief to drive British diplomatic efforts in this field, and we will campaign for the abolition of blasphemy, sedition, apostasy and criminal libel laws worldwide, having already been responsible for ending them in this country.
DUP: Supporting Persecuted Minorities – In the last Parliament, the DUP urged the government to take seriously international human rights abuses against Christians and other faith groups. We continue to be concerned about the persecution of religious
minorities. We will continue to use our influence to ensure that this issue is taken seriously and that the Foreign and Commonwealth Office actively engage with the leadership of the countries in which these human rights violations occur.
Green Party: We will uphold the principles of freedom of speech and peaceful protest, including support for vulnerable communities of all religious faiths and none.
UKIP mentioned only the situation in the UK, with a specific mention of Article 18:
UKIP: UKIP will recognise that British values include tolerance of religion. UKIP is committed to protecting religious freedoms for all believers in the UK, in accordance with Article 18 of the Universal Declaration of Human Rights. We believe, however, that those faiths and beliefs must exist firmly within a British framework. We will not condone any faith position which is itself intolerant and refuses to recognise the human rights of others