Ashers Bakery – the Christian baking company in Northern Ireland – will go before the Supreme Court on Tuesday in a landmark battle between religious freedom and anti-discrimination laws.

The hearing is almost four years to the day since the family-run business first refused to bake a cake with the slogan 'Support Gay Marriage' for LGBT activist Gareth Lee. That decision resulted in a law suit for discrimination being brought against them. After successive appeals, the case has ended up at the highest court in the UK.

Here is a timetable for the case.

May 9, 2014

Gareth Lee, a volunteer with the gay rights group Queerspace, asks Ashers Bakery on Belfast's Royal Avenue to bake a cake decorated with the Sesame Street characters Bert and Bernie and emblazoned with the logo: 'Support Gay Marriage'.

May 12, 2014

Lee receives a phone call from Ashers to say they can't process his order due to conscience grounds and is offered a full refund for his deposit.

June 26, 2014

The Equality Commission for Northern Ireland writes to Ashers saying it had breached the Equality Act (Sexual Orientation) (Northern Ireland) Regulations 2006 which prohibit 'discrimination in the provision of goods, facilities and services to a person seeking or obtaining to use those goods, facilities or services on the grounds of sexual orientation'.

The ECNI asks for a small amount in compensation.

October 27, 2014

After Ashers refused to pay the compensation, the ECNI writes again claiming the company had also breached political and religious discrimination laws.

November 6, 2014

Legal action against Ashers Bakery formally begins.

March 26, 27, 30, 2015

District Judge Isobel Brownlie hears the case over three days at Laganside Courts, Belfast.

Lee says the refusal made him feel like a 'lesser human'.

May 19, 2015

District Judge Brownlie rules Ashers had breached political and sexual orientation discrimination regulations. She says Lee was treated 'less favourably' and orders Ashers to pay £500 damages for injuring the customer's feelings.

'As much as I acknowledge their religious beliefs this is a business to provide service to all. The law says they must do that,' she said.

March 3, 2016

The Court of Appeal's hearing into the Ashers case is dramatically suspended after a late intervention by John Larkin QC, Attorney General in Northern Ireland.

He says the case raised a potential conflict between the region's equality legislation (which is not the same as the 2010 Equalities Act) and European human rights laws.

May 9-12, 2016

The Court of Appeal sits again to hear an appeal against Judge Brownlie's decision in Belfast.

October 24, 2016

Court of Appeal rules against Ashers, finding it was 'direct discrimination' because they would not have objected had the slogan supported heterosexual marriage.

'The fact that a baker provides a cake for a particular team or portrays witches on a Halloween cake does not indicate any support for either,' the judges said in their ruling.

December, 2016

The Court of Appeal leaves the way open for Ashers to take the case further when Lord Chief Justice Sir Declan Morgan said: 'We consider the matter should be properly left to the Supreme Court.'

May, 2017

The UK's highest court, the Supreme Court, agrees to hear the case.

May 1-2, 2018

The Supreme Court will go to Belfast for the first time and hear the Ashers Bakery case.