1. A method of website access control, comprising: accessing, by a communications unit of a user terminal, a plurality of training websites over a network; classifying, by a classification unit of the user terminal, the training websites in a content category based on a user input; extracting, by a feature extraction unit, one or more features indicative of the content category from the training websites; determining, by a classifier determining unit, a classifier for classifying websites in the content category based on the extracted features; verifying, by a verification unit, the determined classifier by accessing, by the communications unit of the user terminal, a plurality of verification websites and classifying the verification websites using the classifier and if the verification websites are classified in the content category, prompting a user to verify the classification of the verification websites; and classifying, by an access control unit, further requested websites using the verified determined classifier and controlling access to the further requested websites based on the classification of the websites, wherein the feature extraction unit, the classifier determining unit and the verification unit form part of the user terminal, the method further comprising: transmitting the verified determined classifier to a server and storing the classifier and a corresponding set of training websites in a memory of the server as part of a plurality of classifiers and a plurality of associated sets of training websites; comparing, by a classifier comparison unit, the plurality of classifiers to determine whether the content categories of each overlap; if the content categories of the plurality of classifiers overlap, extracting, by the feature extraction unit, a plurality of training websites from each of the sets of training websites corresponding to the overlapping classifiers; merging, by the classifier determining unit, the extracted plurality of training websites into a global set of training websites; and determining, by the classifier determining unit, a global classifier based on the global set of training websites.
1. A method of website access control, comprising: accessing, by a communications unit of a user terminal, a plurality of training websites over a network; classifying, by a classification unit of the user terminal, the training websites in a content category based on a user input; extracting, by a feature extraction unit, one or more features indicative of the content category from the training websites; determining, by a classifier determining unit, a classifier for classifying websites in the content category based on the extracted features; verifying, by a verification unit, the determined classifier by accessing, by the communications unit of the user terminal, a plurality of verification websites and classifying the verification websites using the classifier and if the verification websites are classified in the content category, prompting a user to verify the classification of the verification websites; and classifying, by an access control unit, further requested websites using the verified determined classifier and controlling access to the further requested websites based on the classification of the websites, wherein the feature extraction unit, the classifier determining unit and the verification unit form part of the user terminal, the method further comprising: transmitting the verified determined classifier to a server and storing the classifier and a corresponding set of training websites in a memory of the server as part of a plurality of classifiers and a plurality of associated sets of training websites; comparing, by a classifier comparison unit, the plurality of classifiers to determine whether the content categories of each overlap; if the content categories of the plurality of classifiers overlap, extracting, by the feature extraction unit, a plurality of training websites from each of the sets of training websites corresponding to the overlapping classifiers; merging, by the classifier determining unit, the extracted plurality of training websites into a global set of training websites; and determining, by the classifier determining unit, a global classifier based on the global set of training websites. 10. A method according to claim 1 , wherein determining the classifier comprises selecting features present in a number of the plurality of training websites greater than or equal to a valid feature threshold and including the selected features in the classifier.