What are the sources of the constitution?

Acts passed by parliament.
In the US, congress cannot make any ordinary laws that conflict with the higher law of the US Const, however, in the UK, as parliament is sovereign there is no distinction between constitutional and ordinary laws.
Important Statutes: Acts of Union (1707) – united E + S and formed one parliament of GB, The Rep of the People Act (1969) – extended voting to almost all over 18 and Constitutional Reform Act 2005 – created SC which led to clearer sep of power.

Law developed by judicial decisions.
When cases raise similar legal questions to ones decided in the past, judges must use the same reasoning as the earlier court – common law principle of ‘Stare decisis’.
Now, only the SC and Court of Appeal have the power to establish precedent.
BUT parliament is sovereign and therefore statutes override common law.
g. Al Rawi v Security Service (2010) – gov wanted to use ‘closed material procedure’ where ev only shown to judge and not other side, SC said it would undermine CL, parliament passed Justice and Security Act (2010) to allow it.

Conventions are not legally binding and have no definitive source.
They help different branches of gov to operate more smoothly – e.g. monarch asks leader of largest party in the commons to form a gov and be PM – makes sense but not law – this meant that in 2010, where no single party gained a maj, they had to turn to political experts rather than law.
Conventions rely on common agreement and if this breaks down, an act of parliament might become necessary to make to convention legally enforceable – e.g. Pre-1911 Convention – HofL shouldn’t oppose commons on financial matters – opp the 1909 budget – led to Parliament Act (1911).
Some conventions have evolved over time – Royal Assent (app laws) has become more ceremonial as parliament has taken more power.
Others have emerged more quickly, in response to political events – Salisbury Convention (HofL shouldn’t defeat leg from gov’s election manifesto) – after Labour’s victory in 1945 when they only had 16 peers in Lords