The Battle of Grand Gulf was fought on April 29, 1863, during th: The UK does not have a codified constitution and constitutional matters are not among the powers that have been devolved. Under the doctrine of parliamentary sovereignty, the UK Parliament could, in theory, therefore, abolish the Scottish Parliament, Senedd or Northern Ireland Assembly.[196] In practice, it would be politically difficult for the UK Parliament to abolish devolution to the Scottish Parliament and the Senedd, because these institutions were created by referendum decisions.[197] The political constraints placed upon the UK Parliament's power to interfere with devolution in Northern Ireland are greater still, because devolution in Northern Ireland rests upon an international agreement with the Government of Ireland.[198] The UK Parliament restricts the three devolved parliaments' legislative powers in economic policy matters through an act passed in 2020.[199]