Given Ribena’s advertising claims that “the blackcurrants in Ribena have four times the vitamin C of oranges”, they were astonished after discovering there was hardly any, and wrote to the manufacturers, GlaxoSmithKline (GSK). When they got no response, they phoned the company, but were given short shrift. “They didn’t even really answer our questions. They just said it’s the blackcurrants that have it, then they hung up,” Jenny said.

Two New Zealand schoolgirls humbled one of the world’s biggest food and drugs companies after their school science experiment found that their ready-to-drink Ribena contained almost no trace of vitamin C.

Students Anna Devathasan and Jenny Suo tested the blackcurrant cordial against rival brands to test their hypothesis that cheaper brands were less healthy.

Instead, their tests found that the Ribena contained a tiny amount of vitamin C, while another brand’s orange juice drink contained almost four times more.

“We thought we were doing it wrong. We thought we must have made a mistake,” Anna told New Zealand’s Weekend Herald. The girls were both 14 and students at Pakuranga College in Auckland when they did the experiment in 2004.