why is parliament the supreme law making body
Parliamentary sovereignty
The devolution of power to devolved legislatures in Scotland ( Scottish Parliament ) , Wales ( Welsh Assembly ) and Northern Ireland ( Northern Ireland Assembly ) : All three bodies can pass primary legislation within the areas that have been devolved to them , but their powers nevertheless all stem from the UK Parliament and can be withdrawn unilaterally . The Northern Ireland Assembly , in particular , has been suspended multiple times due to political deadlocks . The UK 's membership of the European Economic Community , later the European Union , from 1973 : The EU represents , as the European Court of Justice ruled in 1963 in the case Van Gend en Loos , a `` new legal order of international law for the benefit of which the ( Member ) States have limited their sovereign rights , albeit within limited fields '' . The UK became part of that legal order , though as UK membership of the EU has been brought about through Acts of Parliament -- principally the European Communities Act 1972 -- Parliament could , as a matter of UK law , pass further legislation unilaterally withdrawing the UK from the Union , or selectively barring the application of European law within the UK . The European Union Act 2011 reaffirmed that sovereignty lay with the British Parliament , with section 18 stating : `` Directly applicable or directly effective EU law ( that is , the rights , powers , liabilities , obligations , restrictions , remedies and procedures referred to in section 2 ( 1 ) of the European Communities Act 1972 ) falls to be recognized and available in law in the United Kingdom only by virtue of that Act or where it is required to be recognised and available in law by virtue of any other Act . '' The Act also requires that a referendum be held when more powers are transferred to the European Union ( though this can be repealed with another Act of Parliament ) . Alternatively , as prescribed by the 2016 Brexit referendum , an Act to withdraw from the European Union could be passed in parallel with the withdrawal procedure laid down in Article 50 of the Lisbon Treaty , whereby a Member State would notify the European Council of its intention to secede from the Union and a withdrawal agreement would be negotiated between the Union and the State . The Treaties would cease to be applicable to that State from the date of the agreement or , failing that , within two years of the notification . Following the case of Thoburn v Sunderland City Council certain statutes are perceived to be protected as Constitutional Statutes . The case involved amendments to the Weights and Measures Act 1985 by the Weights and Measures Act 1985 ( Metrication ) ( Amendment ) Order 1994 pursuant to Directive 80 / 181 / EEC . This stated that Imperial measurements could be displayed so long as the metric measurements were displayed in larger type beside them . Thoburn was convicted for only displaying Imperial measurements . In his defence he argued that allowing even limited use of Imperial measurements was inconsistent with the European directive and therefore in contravention of Section 2 ( 2 ) of the European Communities Act 1972 , and that the relevant section of the 1972 Act had therefore been implicitly repealed . However , the judgement by Lord Justice Laws held that certain statutes of constitutional importance , including Magna Carta and the European Communities Act 1972 , could not be repealed by implied repeal . The case also introduces the concept of a ' hierarchy of acts ' , which is used in other European countries , to English constitutional law . However , if Parliament did make its intention to overrule any statute express then any statute can be repealed , and so sovereignty is preserved . The enactment of the Human Rights Act 1998 which incorporates part of the European Convention on Human Rights into domestic law . The Act gives UK courts the power to issue a declaration of incompatibility where they believe that the terms of an Act of Parliament are in contravention of the rights guaranteed by the Human Rights Act . The effect of the declaration is not to annul the contravening Act but to send a signal to Parliament which may then choose to amend the offending provision . This does not endanger Parliamentary sovereignty because Parliament may choose not to amend the offending provisions . As with the UK 's membership of the European Union , the principle of parliamentary supremacy means that Parliament can at any time vote to repeal the Human Rights Act , and indeed the UK 's ratification of the Convention itself .
The devolution of power to devolved legislatures in Scotland ( Scottish Parliament ) , Wales ( Welsh Assembly ) and Northern Ireland ( Northern Ireland Assembly ) : All three bodies can pass primary legislation within the areas that have been devolved to them , but their powers nevertheless all stem from the UK Parliament and can be withdrawn unilaterally . The Northern Ireland Assembly , in particular , has been suspended multiple times due to political deadlocks . The UK 's membership of the European Economic Community , later the European Union , from 1973 : The EU represents , as the European Court of Justice ruled in 1963 in the case Van Gend en Loos , a `` new legal order of international law for the benefit of which the ( Member ) States have limited their sovereign rights , albeit within limited fields '' . The UK became part of that legal order , though as UK membership of the EU has been brought about through Acts of Parliament -- principally the European Communities Act 1972 -- Parliament could , as a matter of UK law , pass further legislation unilaterally withdrawing the UK from the Union , or selectively barring the application of European law within the UK . The European Union Act 2011 reaffirmed that sovereignty lay with the British Parliament , with section 18 stating : `` Directly applicable or directly effective EU law ( that is , the rights , powers , liabilities , obligations , restrictions , remedies and procedures referred to in section 2 ( 1 ) of the European Communities Act 1972 ) falls to be recognized and available in law in the United Kingdom only by virtue of that Act or where it is required to be recognised and available in law by virtue of any other Act . '' The Act also requires that a referendum be held when more powers are transferred to the European Union ( though this can be repealed with another Act of Parliament ) . Alternatively , as prescribed by the 2016 Brexit referendum , an Act to withdraw from the European Union could be passed in parallel with the withdrawal procedure laid down in Article 50 of the Lisbon Treaty , whereby a Member State would notify the European Council of its intention to secede from the Union and a withdrawal agreement would be negotiated between the Union and the State . The Treaties would cease to be applicable to that State from the date of the agreement or , failing that , within two years of the notification . Following the case of Thoburn v Sunderland City Council certain statutes are perceived to be protected as Constitutional Statutes . The case involved amendments to the Weights and Measures Act 1985 by the Weights and Measures Act 1985 ( Metrication ) ( Amendment ) Order 1994 pursuant to Directive 80 / 181 / EEC . This stated that Imperial measurements could be displayed so long as the metric measurements were displayed in larger type beside them . Thoburn was convicted for only displaying Imperial measurements . In his defence he argued that allowing even limited use of Imperial measurements was inconsistent with the European directive and therefore in contravention of Section 2 ( 2 ) of the European Communities Act 1972 , and that the relevant section of the 1972 Act had therefore been implicitly repealed . However , the judgement by Lord Justice Laws held that certain statutes of constitutional importance , including Magna Carta and the European Communities Act 1972 , could not be repealed by implied repeal . The case also introduces the concept of a ' hierarchy of acts ' , which is used in other European countries , to English constitutional law . However , if Parliament did make its intention to overrule any statute express then any statute can be repealed , and so sovereignty is preserved . The enactment of the Human Rights Act 1998 which incorporates part of the European Convention on Human Rights into domestic law . The Act gives UK courts the power to issue a declaration of incompatibility where they believe that the terms of an Act of Parliament are in contravention of the rights guaranteed by the Human Rights Act . The effect of the declaration is not to annul the contravening Act but to send a signal to Parliament which may then choose to amend the offending provision . This does not endanger Parliamentary sovereignty because Parliament may choose not to amend the offending provisions . As with the UK 's membership of the European Union , the principle of parliamentary supremacy means that Parliament can at any time vote to repeal the Human Rights Act , and indeed the UK 's ratification of the Convention itself .