We have already seen that Britain's entry into the European Treaty's has invoked huge reform. (British) Parliament must now legislate in conjunction with EU law, Acts and Laws already in existence must be interpreted to conform to EU Law and the State has to ensure that all EU law is transposed and implemented accurately. This puts a huge strain on the Courts whilst ruling, thus making a mockery of Precedent as any case incorporating EU legislation can only be considered using the purposive approach, in order that EU directive can be met. So then, has Britain reserved its sovereignty as promised?
As a result of joining the EU English law has seen the introduction of EU primary legislation i. e. treaties, e. g. the treaty of Rome. It has also signalled the introduction of secondary legislation, which includes regulations, directives, decisions and recommendations and opinions. The introduction of treaties and directives etc has prompted an increase in the force and quantity of human rights law in England, but some say for the cost of parliamentary sovereignty in the UK. This has lead many to believe in the so-called 'Eurocrats' trying to govern the whole of Europe without any consultation of it's member states.
EU secondary legislation has many different levels, which allows for the correct weight to be applied to each 'Act' for use in the EU. Regulations create new laws and are directly applicable, which means they do not need any action to be taken by government to inforce it. However, directives that do not create new laws but aim to harmonise existing law between members of the EU need some form of implementation. E. g. the Product Liability Directive of 1985 was implemented in UK by the Consumer Protection Act 1987.
The issue of direct effect has also come around with membership of the EU. The two types of direct effect are vertical (where one is suing the government) and horizontal (where one is not suing the government). In the case of Van Duyn v. The Home Office, The European Court decided that where the purpose of a Directive was to grant rights to the individuals and the Directive was sufficiently clear it would be directly enforceable by an individual against the member state, even thought that state had not implemented the Directive by the set date.
Vertical direct effect has evolved over the years of EU influence to a point where it is relatively easy for an individual to take a state to court and win. In the case of Marshall v. Southampton Area Health Authority. Mrs. Marshall wanted to work till she was 65 like her male counterparts, but she was made to retire at 62 because of the lower retirement age for women. She took Southampton A. H. A (a distant arm of the state) to court and won under the Article six of the Equal Treatment Directive (76/207) which was found to have direct effect over the case.
She only won because her employers were an arm of the state. This also has Euro sceptics up in arms as to the supremacy of the English Parliament. Directives that have not been implemented do not, however, give any individual rights against other people. So, in Duke v. GEC Reliance (1988), Mrs. Duke was unable to rely on the Equal Treatment Directive 76/207 as her employer was a private company. Therefore, it is said that Directives do not have horizontal effect. This can also be seen in the Italian case of Paola Faccini Dori v.
Recreb Srl, (1994). Surely giving any citizen the rights to challenge the State can only be met with approval, and in the case of Frankovich v Italy  this was indeed the case. Failure on behalf of the Member State to incorporate a Directive within the allotted time scale meant that a claim could proceed against the Italian Government for compensation, obscuring the distinction between horizontal and vertical effect. But the cost of challenge is great, tying up lengthy periods of Court time and vast sums of money.
These rights are not always maintained, the UK, for example, refers fewer cases than the other member states to the European Court of Justice since the lower Courts are allowed to exercise discretion on referral. The EU giveth, the Government taketh away. It can be thought that the increased introduction of direct effect is a good thing as it allows for more injustices to be rectified, or not caused at all. Direct effect will also have repercussions upon English judges as they may feel that their rulings are more vulnerable to being challenged by the EU.