Was in the same position about four years ago. Check your contract and run it by a good lawyer (contradiction in terms I know!!). Got offered the job with my current employer with three days notice (course dropout). I turned the job down even though I had no contract, but was lucky enough to get a second chance a couple of weeks later. This allowed me to give a months notice which I thought fair. They decided that I should have given 3 months notice and dismissed me on the spot!!! I was a mug! I lost a months wages and paid the price for being trusting my then emloyers... Moral .. look after Number One if it's legal. You may not get a second chance. Good Luck.