Internet pornography is having a damaging impact on young people's views about sex and puts pressure on girls to look and act a certain way, according to a poll of 500 British teenagers.

Eight out of 10 18-year-olds surveyed by the thinktank IPPR felt it was too easy to accidentally view explicit images while surfing the internet, while 72% said pornography led to unrealistic views about sex.

In findings that will add to concerns over the sharing of explicit photographs, 46% of 18-year-olds polled said sending sexual or naked photographs and videos was "part of everyday life for teenagers nowadays".

"This new polling data shows that pornographic images are pervasive in teenagers' lives and that young women in particular are acutely conscious of how damaging they can be," said Dalia Ben-Galim, associate director of IPPR.

Almost eight out of 10 young women said pornography had led to pressure on girls to look and act a certain way, while 66% said "it would be easier growing up if pornography was less easy to access for young people".

Most young men and women in the Opinium poll said viewing pornography had become typical when they were aged 13 to 14, although 10% of respondents said it was common among children as young as 11.

When asked about sex education, 61% said adults were out of touch with the relationships of young people and 56% said adults found it hard to understand or help with online issues.

Ruth Sutherland, chief executive of the charity Relate, said the poll highlighted a need for change in how schools teach sex education. "The relationship skills we build as young people are crucial to how we form our couple, family, social and professional relationships later in life," Sutherland said. "But the way those early relationships are conducted has changed immeasurably in the last 10 years, leaving a gulf between this generation and the previous ones."