Younger couples are citing the environment as one of the most common reasons for deciding to remain childless, a poll has shown.

One in seven adults under 35 who don’t want children say they believe the world has too many people, with one in ten saying children would add to climate change pressures.

The birth rate is already at a record low in England and Wales due to an ageing population and women delaying childbirth and having fewer children to focus on their careers. The average number of children born to women dropped to 1.7 last year, compared to an average of 2.9 children in the peak of the early 1960s, while one in five women in their early 40s was childless, the third