The minarets of the East London Mosque, the largest mosque in Britain. (Matt Dunham/AP)

A new poll appears to paint a stark picture of British Muslims and their apparently complicated attitudes toward modern Western values. However, it has also sparked a fierce debate about the accuracy of such polls, with some even questioning whether they should be conducted at all.

Just over half of British Muslims said homosexuality should be illegal, according to the poll, while almost a quarter thought that sharia law should be implemented in some areas of Britain and just under a third said polygamy, which is illegal in Britain, is an acceptable practice for Muslims. Perhaps more concerning, a majority of Muslims polled said they would attempt to personally intervene rather than contact police if someone they knew was getting involved with people who support terrorism in Syria.

The poll was conducted by ICM Research for the Channel 4 documentary "What British Muslims Really Think," set to air Wednesday. In an article published Sunday, Trevor Phillips, the host of the documentary and a former head of Britain's Equality and Human Rights Commission, said that the new data shows a "chasm" between many British Muslims and their compatriots and that there was a danger that Britain's Muslim community could become a "nation-within-a-nation."

The survey has sparked a considerable backlash, not only for its methodology but also over the wisdom of conducting polls that focus on a religious minority in such heated times. There are significant doubts about whether the survey’s sample is representative of the British Muslim population at large.

At the least, the widespread focus on attitudes toward the rights of women and homosexuals has perhaps overshadowed the positive takeaways from the poll: 86 percent of British Muslims said they felt a strong sense of belonging in Britain, with 88 percent suggesting that Britain was a good place for Muslims to live and 78 percent saying they were keen to integrate into British life, with the exception of Islamic schooling and some sharia laws.

Notably, the poll also found little support for terrorism, with 85 percent saying they condemn those who take part in suicide attacks, and 73 percent saying they opposed how the Islamic State was trying to create a caliphate (just 3 percent said they supported it).

The divergence between British Muslims and other British citizens on key issues is hard to deny, however. As Phillips noted in an article for the Daily Mail newspaper, just 9 percent of non-Muslim Britons agree with the idea that Jews held too much power, compared with 35 percent of British Muslims surveyed in his poll. He pointed to another figure to help explain this: A fifth of British Muslims have apparently not entered the home of a non-Muslim friend in the past year.

This isn't the first poll on British Muslims to produce controversial results, nor is it the first whose methodology has been criticized. Given the rise of the Islamic State in the past few years and the large number of European citizens who have gone to fight alongside the militant group (and, in some cases, returned), interest in the attitudes and beliefs of Europe's Muslim minority has grown.

Some opinion polls dealing with the subject have been attacked for a lack of rigor. The Sun newspaper was recently forced to print a correction for a report in which it cited a poll suggesting that one in five British Muslims supported people who had gone to Syria to fight for jihadist groups. The Washington Post's polling expert Scott Clement was among those who took issue with the way that poll was conducted and the way its results were presented, noting that the question was worded too vaguely to provide firm conclusions about the responses. The survey’s sample was also limited to people with “Muslim names,” a method that excluded an unknown percentage of the Muslim population.

Phillips has called the new "What British Muslims Really Think" poll the "most comprehensive survey of British Muslims ever conducted." It is notable for its scope: face-to-face interviews with 1,081 British Muslim adults from April 25 to May 31, 2015, in their homes. That's a big endeavor. These days, many polls are conducted online, which can easily skew the audience.

It is also, however, an expensive endeavor. As British actor Adil Ray and others have pointed out on Twitter, ICM Research claims to have limited its survey to "geographical areas" of the country where Muslims make up more than 20 percent of the population.

The Post's Clement suggests that the only reason for focusing on an area with a heavy Muslim presence would be financial cost. "It’s cheaper to interview a sizable sample of Muslims in areas where they are concentrated," he says.

That could be a problem, however. Muslims make up only about 4 percent of Britain's population and tend to be spread out rather than concentrated in small areas. Critics have argued that ICM may have been limiting its view of British Muslims to those who live in Muslim-heavy areas — areas that may be unrepresentative both ethnically and socioeconomically.

Martin Boon of ICM Research has confirmed that the survey used geographic units of about 1,500 people where at least 20 percent of the population was Muslim. Boon says that 51.4 percent of Britain's Muslims live in these areas. Although that coverage rate is higher than some critics had extrapolated, it is far from enough to dispel all doubts — many general-population telephone surveys have coverage rates well over 90 percent, because nearly the entire population has a land line or mobile phone. The limited sample range of the ICM survey presents significant problems. Muslims who live in areas with large Muslim communities may well have different views on assimilation and religion from those who do not. ICM’s data cannot tell us either way, as these people never had a chance of being contacted.

The Post has reached out to the group for more information. Additionally, it is unclear from the information released what languages the interview were conducted in and how the data was weighted to be representative of Britain's Muslim population.

Even if ICM is able to explain away these problems, questions will probably linger about the poll's findings and the presentation of those findings. Phillips, a former Labour Party lawmaker, is a vocal opponent of multiculturalism, which he believes could be leading Britain toward segregation. ICM has already been involved in one strange case regarding polling of a Muslim minority: In 2014, it was behind research that appeared to show that one in six French citizens supported the Islamic State, a poll in which the methodology appeared relatively sound but the results were extremely surprising.

The controversy surrounding the latest poll raises key issues. Polling any minority is always hard — it takes time, money and effort to find members of a minority willing to speak. The polling of European Muslims may be even more difficult, given the political climate and other issues such as language. (Pew Research is a notable outlier in this regard in the United States, using screening from national general-population samples combined with targeted samples of those with common Muslim surnames to reach near-universal coverage, Clement says.)

Even in the best circumstances, the resulting data from these surveys is interpreted through a lens that reflects Europe's complicated relationship with its Muslim minority. As Kenan Malik, a London-based writer and lecturer, notes on Twitter, the results of the latest poll may betray this: While only 34 percent of British Muslims said they might contact police if someone close to them was involved with terrorism in Syria, ICM also found that just 30 percent within a non-Muslim control group said they would go to the authorities in the same situation.

In fact, ICM's data seemed to show that in a variety of ways, British Muslims felt more British and had less tolerance for extremism than their non-Muslim peers. For some, the controversy over the "What British Muslims Really Think" poll shows why these surveys are not helpful in the grand scheme of things. "Polls alienate," Ray tweeted on Monday, suggesting that "reckless polling and reporting divides us further."

Meanwhile, other critics have found more lighthearted ways to criticize the situation.

More on WorldViews:

Do 1 in 6 French citizens really support Islamic State?

Switzerland shocked by Muslim teens who refused to shake hands with female teachers

State Department: Kerry recognizes that calling ISIS ‘apostates’ was not ‘the best choice’

Correction: The original version of this article inaccurately described the poll's findings on how British Muslims view the Islamic State's attempts to create a caliphate. The text has been edited to better reflect the poll's findings.