Masood Ahmad is 72. A British-Pakistani dual national, he returned to his native Pakistan in 1982 after working in London for some years to pay his children’s school fees. On his return, he opened a pharmacy and homeopathic clinic in the large eastern city of Lahore.

Last month, two men visited his clinic, posing as patients. They questioned him about his faith, and used their mobile phones to secretly record him reading a verse from the Qur’an.

Soon afterwards, he was arrested on charges of blasphemy.

Dr Ahmad, a quiet, reserved widower who still has family in the UK, is a member of the minority Ahmadi sect. In 1974, they were declared non-Muslims, and banned from 'posing as Muslims'. This comes down to a theological dispute. Ahmadis believe that the Mirza Ghulam Ahmad, who founded their movement in 1889, was a prophet. This contradicts the mainstream Islamic belief that Muhammad was the final prophet of God.

Ahmadis, who define themselves as Muslim and view the Qur’an as their Holy Book, are technically breaking the law every time they practice their faith. This community of around 4 million refuses to vote: doing so would be tacit acceptance that they are not Muslim.

Last year, in the run up to Pakistan’s historic general election in May, I met with one of the Ahmadi community’s figureheads. Saleem Uddin, a softly spoken man who prefers not to be photographed, normally resides in the community’s headquarters, the city of Rabwah, where 90 per cent of Ahmadis live. (Conservative religious leaders have twice sought to have the whole city arrested for holding religious celebrations). I met Uddin in Islamabad. After a discussion of the vote boycott, he handed me a thick report detailing every incident against Ahmadis that year. It made sobering reading.

Page after page described vigilantes breaking into Ahmadis’ houses and forcibly removing Arabic inscriptions of Qur’anic verses. There were never any ramifications; sometimes this was the work of the police themselves. Across the country, Ahmadi places of worship had faced legal challenges from local councils and residents. Translations from the Urdu-language press demonstrated the constant drip-feed of hatred (One example, from the Daily Khabrain: “Apostates must be killed. To declare Qadianis [a derogatory name for Ahamdis] as a non-Muslim minority was an act of generosity for them”).

There are currently upwards of 280 legal cases registered against Ahmadis for “impersonating Muslims”. Those carrying out more violent crimes – such as the extremists who desecrated more than 100 Ahmadi graves in Lahore in 2012, or those who killed more than 90 in a bombing at an Ahmadi mosque in the city in 2010 – know that they need not worry about ramifications. This reflects a wider pattern in Pakistan where the formalised persecution of minorities provides space for sectarian violence to grow. Similar trends can be seen in the treatment of the Christian and Hindu communities (who have been subject to bomb attacks and smaller vigilante attacks after blasphemy charges against individuals).

For improvement, Uddin said, “Religion must stop being the dominant force in politics.” Sadly, in today’s Pakistan, the opposite trend is evident, as mainstream politicians, terrified by the extremist threat, are allowing such groups to dictate the national conversation. Attempts to reform the country’s repressive blasphemy laws in 2009-10 were shelved after two of the ministers driving the process were assassinated. Three years later, the situation for religious minorities is worse than ever.

Dr Ahmad and his family are appealing to the British High Commission for help but as yet, no statement has been made. Blasphemy cases attract high levels of public emotion, with mob violence often resulting in deaths before cases have even been heard. Crowds have been gathered outside the jail where the elderly doctor is being held, chanting anti-Ahmadi slogans. “I used to read about minorities being targeted in the newspapers,” Dr Ahmad told the BBC. “Now I’m in the news.”