Yes, Corbyn is a threat - to his own party and to those who don't relish another generation of Tory rule. Do you REALLY believe I am the only ordinary voter who thinks Corbyn is a complete disaster for his party, and for the concept of democracy in this country generally? Get real.
So what is the concept of democracy in the UK?
a. system of government by the whole population or all the eligible members of a state, typically through elected representatives.
b. control of an organization or group by the majority of its members.
c. the belief in freedom and equality between people.
it seems to be more like "having a general election every five years where we can choose between two groups who, pretty much, will do the same things when elected: to whit raise taxes to fund their political whims and screw the needs and wishes of the population". The latter [screw the wishes of the population] may or may not be a bad thing.