One Direction stars Louis Tomlinson and Zayn Malik are under increasing pressure to speak out in the aftermath of their weed video scandal following harsh criticism from anti-drugs campaigners.

The pop singers hit headlines this week (beg26May14) when footage emerged showing them puffing on a suspicious-looking cigarette in a car in Peru, and talking about "illegal substances" and "Mary Jane", a nickname for marijuana.

Neither Tomlinson nor Malik have addressed the scandal directly, but they are now facing calls for an apology amid growing criticism and harsh words from anti-drugs campaigners, who allege the stars are a bad influence on their young fans.

Lucy Dawe, of charity Skunk Sense, tells Britain's Daily Star newspaper, "This is utterly irresponsible when One Direction have an extremely young following and we know cannabis damages young brains. The huge worry is that they're in a position to be role models and they're actually being extremely poor role models and pulling young people into drug use...

"It's completely indefensible. These boys have the money behind them that they can get help if they become ill from using cannabis. But we don't have any teenage rehab facilities in the Uk."