The world’s leading vaping brand is planning a significant UK expansion, including the marketing of fruit flavours that critics have said are designed to appeal to teenagers.

Juul, which has been stocked in Boots, Sainsbury’s and specialist e-cigarette stores since last July, now intends to offer its products in around 55,000 British outlets, the company has confirmed.

Among the flavours it will offer more widely are apple, mango and berries, despite ceasing selling these products in the US following an outcry that they were luring young people into vaping.

However, the company said none of its products are marketed at children and that it does not pay “social influencers” to promote them.

This comes as a leading teaching body warned about the rise of vaping in schools.

Shaun Fenton, chair of the Headmasters and Headmistresses’ Conference, which represents top public schools, told The Sunday Times: “Children are not smoking - they are vaping instead.