But power isn't only instilled by a rule book. It is also increased in the face of weak opposition to its exercise. Ken Livingstone, as mayor of London, gained control over the GLA and its agencies, largely because no-one dared contest his dominance. Conversely, the Queen would have difficulty using the powers she holds in statute, purely because they have wasted away through disuse.
This is how Labour Party rules have to be viewed. Until 1997, though rarely used, nomination forms for leader of the Labour Party were issued every year. After 1997, the party ceased doing so because few people wanted a change. So year after year this new precedent emerged simply because MPs, members and the unions failed to react against this diminishing of their power.
Now a number of MPs want nomination papers and are surprised their authority to exercise this small power has disappeared because they had spent ten years loyally refraining from exercising it. Had they insisted on nomination papers every year and nominated Tony Blair, they would have protected their power.
The National Executive Committee (NEC) this week overruled this request from what is believed to be up to 30 MPs. And the NEC can do this precisely because the members of the Labour Party have failed to protect their influence by demanding good internal democracy. The 33 members of the NEC are overwhelmingly representative of powerful vested interests; Labour Party members directly elect only six seats. In fact the only time party members have any influence over the NEC is when the unions and the Government disagree, which they usually arrange before meetings not to do.
So whom can Labour members blame for this? Only themselves, for not electing NEC members less susceptible to powerful interests and for failing to select candidates and elect MPs who take seriously the concept of democracy within the party.
Alex Hilton is a Labour parliamentary candidate and founder of political blogs Labourhome and Recess Monkey.