Never been asked for a reference - they're worth bugger all anyway.
Employers cannot give negative references now - they can only state facts and offer neutral 'omissions' rather than slate an employee.
What do they expect to find out from a reference anyway? If the rest of the recruitment process can't determine your suitability are they going to get any useful information from previous employers (where you left usually because you wanted something better or the employer wanted someone better instead of you!)?
Certainly don't speak to your existing employer about a reference. That's only going to negatively affect you if you don't get the new job.
