EEO, my favourite subject!
Not sure what the law is in the UK, but Down Under an employer is able to place certain requirements on an employee for reasons such as safety.
For example, some airlines state that FA candidates be of a certain height - as they need to reach emergency equipment and/or operate doors/exits and to do this you must be a certain height. This is considered to be fair and reasonable.
Same applies for weight. Obviously it is not in the public safety's interest to have a crewmember who is clearly overweight and unfit, as this could potentially obstruct or hinder an evacuation if necessary.
However due to a court case a few years ago instigated by some FAs in the USA (who won their case by the way), airlines are not permitted to discriminate against people who they deem to be 'overweight'. Hence the "weight in proportion to height" requirement. To my knowledge there is no CAA regulation as to how much a FA needs to weigh.
Hope that helps!
SG
