Spanish police have arrested a British man suspected by French authorities of being the head of a cocaine trafficking network, the interior ministry said Monday.It identified the man as Martin Lance N., 40, also known as "Martin the Bag", born in the central English town of Oadby near Leicester and a resident of the southern Spanish resort of Marbella.It said he was detained in the northeastern city of Barcelona.He is the object of an international arrest warrant issued by French authorities."He is suspected of being the head of a group involved in importing, manufacturing, producing, providing or acquiring narcotics, specifically cocaine," an interior ministry statement said.In particular, French police believe he was involved in smuggling 144 kilogrammes (317 pounds) of cocaine hidden in four mattresses that were found in Paris in June 2006.