In addition to the basic Common Law rules relating to contract, many contracts now have supplementary rules provided by statute. This is where, in England for example, Parliament has decided that the basic Common Law rules have required either supplementation, amendment or updating. These include: Under English law, The Sale of Goods Act 1979 (supplemented by the Sale and Supply of Goods Act 1994 and the Sale of Goods (Amendment) Act 1995) applies to specific types of contracts only – those where the ownership of the goods is exchanged for money. The Act includes specific implied terms which are to be deemed as incorporated into the contract, for example, those dealing with the quality and fitness of purpose of the goods. The Supply of Goods and Services Act 1982 applies to certain contracts for services and materials supplied. Such contracts will not fall within the Sale of Goods Act 1979 and therefore, the 1982 Act provides similar provisions in relation to contracts for the supply of goods and services as are found in the 1979 Act in relation to contracts of sale. The Factors Act 1889 has codified and amplified the Common Law in relation to mercantile agents. It includes agents having a general lien on goods in their possession and on the proceeds of sale of such goods for the balance of account between the agent and his principal. A lien is a right and a general lien is a right to retain possession of the goods of another until all claims against that other have been satisfied. By well-recognised usage, a general lien exists in the case of solicitors, mercantile factors, stockbrokers and bankers. By contrast, a particular lien is a right to retain goods until all charges incurred in respect of those goods have been paid. Common carriers have a lien in respect of the freight on the goods carried. Both general liens and particular liens are said to be ‘possessory liens’. A possessory lien is dependent upon the holder of the lien being in possession of the goods.