You can pass the name to your neighbourhood police team, but it is possible that they already are aware of the individual concerned. They will probably ask you how you know this information; is there any way that you can prove he is a drug dealer? I mean to say, it may seem obvious to all and sundry but that does not mean that the person actually IS a drug dealer. Have you seen large amounts of drugs at his / her property / on their person? Have you actually witnessed somebody giving them money in exchange for drugs? Without evidence there is very little the police can do, but should other witnesses come forward and also report the same person then the police could set up surveillance operations / increase spot checks, etc.