No, its not mandatory. If you completed an apprenticeship as a Chef, then you are required to show 3 years of paid work experience pre or post qualification. If you are from the UK and hold an NVQ3 as a Chef, you would require the 3 years work experience as a Chef.
If you do not hold an NVQ3 as a Chef, then you are required to have a minimum of 5 years paid work experience as a Chef.