You have just received a job offer over the telephone and you are delighted. Immediately you do not hesitate in typing up a resignation letter and handing it to your boss. Job done. But are you being wise in acting so swiftly?
The short answer is no. A verbal offer of a job is only as good as the paper it is written on. Should the offer be subsequently rescinded, it is your word against your potential future employer that the offer existed in the first place. In essence, you should always wait until you receive a soft or a hard copy of a conditional job offer. This offer should set out in clear terms the salary, a summary job description, conditions that need to be met before commencing(reference checks etc), location, working hours, pension contributions(if applicable), health insurance (if applicable), your suggested starting date and any other details that may be pertinent to the role.
After carefully reviewing the job offer you should get back to your future prospective employer in regards any queries or clarifications you have in regards the job offer. When any creases have been ironed out through negotiation, it is important that you accept the job offer in writing.
You are nearly there. If you are happy with the offer and want to accept it, the next step is to check your current employment contract in regards how much notice period you are required to give, to type up a resignation letter and hand it personally to your direct boss.
In essence, you should never hand in your notice before an offer is received and accepted in writing. Otherwise, you run the risk of a verbal offer being rescinded and an employer lacking scruples denying they made the job offer in the first place.