I agree with Brendan that the terms of the contract should be respected absolutely.
My problem is that I started a new job 2 weeks ago. On paper, it all looked good. A six figure basic, bonus up to 40%, car, pension, shares, healthcare, etc.
On Tuesday afternoon of last week, my boss asked me to have a report ready for him for first thing on Wednesday morning. When I told him that I anticipated that this would take at least 6 hours, he gave me a "and your problem is" type look.
My contract is 9 to 5, Monday to Friday with a reference to exceptionally having to work outside these hours. When I consulted my new colleagues, I was advised to get used to it as that's just the way it is around here.
So what do I do? I have noticed that pretty much all of my colleagues work in excess of the contracted hours and I really feel very uncomfortable about the prospect of having to work in an environment in which I am expected to consistently act in breach of my contractual terms.
I would find an employees attitude of 'a contract is a contract' with regard to working hours as annoying as I would find an employer saying a 'contract is a contract' with regard to a notice period. Especially at the level that you are obviously at. Most employer /employee relationships or at least the good ones are built on mutual flexibility. I have always worked as early and as late as was necessary despite my contract saying 9-5 but I would always expect my employer to be flexibile with me if I needed a few hours off and my work wouldn't be affected.
As for what to do, apparently you simply work your contracted hours if you wish and walk out the door at 5 every day. What can your employer do? You signed a contract and morally and legally they will just have to accept it.