The girls were arrested before boarding their flight to London

Yasemin Vatansever and Yatunde Diya, both aged 16 and from London, were held as they tried to board a plane in Accra while allegedly carrying cocaine.

The pair say they were not aware that the drugs - said to be worth about �300,000 - were in their luggage.

They appear before court on 18 July. If found guilty they could face at least 10 years in jail.

Catherine Wolthuizen, from Fair Trials Abroad (FTA), said: "The families are totally overwhelmed."

She said the girls' parents had not even been aware their daughters were in Africa, adding: "They are looking to go out to Ghana as soon as possible."

Basic conditions

Yasemin is the daughter of immigrants from Cyprus, while Yatunde is of Nigerian descent. Both are UK citizens.

The Foreign Office said the pair were arrested at Kotoka International Airport on 2 July and charged with possessing and attempting to export an illegal substance.

"There is no prisoner transfer agreement between the UK and Ghana," said Ms Wolthuizen.

"So if they are found guilty they could end up serving their sentence in a Ghanaian prison.

"Prisons conditions there are very basic. The girls will be reliant on the High Commission to provide them with food."

It was basically like a set-up Yasemin Vatansever

FTA is ensuring the girls have proper legal representation in Ghana and is providing support to their families in the UK.

Ghanaian authorities were said to have found the drugs in laptop bags carried by the girls.

Two Ghanaian men apparently paid for the teenagers' accommodation in Accra.

The girls have told police the men gave them the laptop bags.

Yasemin told Channel 4 News on Thursday night they were tricked into carrying drugs to London.

Speaking by telephone from prison in Accra, she said: "There were basically two boys over here who gave us two bags and told us... it was an empty bag.

"We never thought anything bad was inside... and they told us to go to the UK and drop it off to some boy... at the airport."

"It was basically like a set-up. They didn't tell us nothing, we didn't think nothing, because basically we are innocent.