In the context of the UKs membership of the EU and the advent of devolved administrations, is it still possible to regard the UK as a centralised, unitary state?

The United Kingdom has a unitary, rather than a federal, constitution. Since the Act of Union with Scotland 1707, legislative and executive authority has been concentrated in the Westminster Parliament and the government in London. That has remained the position until the introduction of devolution measures by the Labour government elected in 1997. Since the Treaty of Maastricht 1992, the European Union, and the rules of community law, now exercise an enormous influence on the United Kingdom, including its constitutional law. In effect, it has modified the principle of parliamentary legislative supremacy, which the courts had consistently upheld for the last 300 years….(short extract)