depends whats written in your contract. then it depends if u want to keep the job

Who's demand?

[iReal world[/i demand, innit?

Check it and see if it includes any mention of something like 'plus any reasonable overtime deemed necessary by the company.............'

My contracted hours are 40 hrs Monday to Friday, plus this type of clause. Our staff association are taking legal advice as to the definition of reasonable as since we have had several redundancies in certain positions, there has been regular occurrences of 50+ hours being logged.

The OP wants to thank his lucky stare he is in full-time employment!
Doesn't he realise there are millions just waiting to jump into his boots?

Just because there is high levels of unemployment should not mean people should take being crapped on as a sign of gratitude for being in work