i think your employer has an obligation under the Health & Safety at work act 1974 to provide you with a safe plant/systems of work which also include the appointment of health and safety reps/ advisors.
the type of job you do should also have been risk assessed and graded.
if it is a high risk job then there should be at least 1 first aider on site at all times.
at my place of work Team leaders and shift managers are all first aid trained also all members of site security are first aiders. as before, check out the HSE website for more info chap.
happy hunting
james