The Employment Appeal Tribunal (EAT), in Gibson v Scottish Ambulance Service,
has considered the appropriate test to be applied under the Part-time Workers
(Prevention of Less Favourable Treatment) Regulations 2000 (PTW Regulations).

Under the PTW Regulations, a part-time worker has the right not to be treated
less favourably than a comparable full-time worker concerning the terms of
his contract or suffer any other detriment from his employer. This right only
applies where the less favourable treatment is on account of the part-time
worker's status and the employer cannot justify such treatment on objective
grounds. Under the PTW Regulations, a pro rata principle will be applied to
determine whether a part-time worker has been treated less favourably, unless
it is inappropriate to do so. Mr Gibson claimed less favourable treatment on
the basis that he spent an average of 56 hours per week on standby whereas
a full-time comparator based in a different region, averaged only 35 hours
per week. It was accepted by both parties that this was contrary to the pro
rata principle.

It was submitted for Mr Gibson, that 'but for' his part-time status he would
have had the same standby hours as his full-time comparator. The tribunal decided
that the 'but for' argument was the wrong test and, even it was the right test,
Mr Gibson would not succeed in his claim as the evidence suggested no single
determinant of part-time status, but rather a combination of factors which
included his status as a part-time worker. The Employment Tribunal applied
a 'subjective' test which involved considering the reasons why Mr Gibson was
rostered for a proportionately higher number of standby hours than the named

On appeal, the EAT held that the tribunal had taken the correct approach in
applying a subjective test. The application of this test indicated that the
main reason for the extra number of hours spent on standby by Mr Gibson was
high local demand. It was also found to be relevant that other part-time workers
were on different working patterns, which did not offend the pro-rata principle
and therefore the treatment could not be said to be solely attributable to
his part-time status.

This does appear to be a particularly restrictive interpretation of the PTW
Regulations and it is interesting to note that the dissenting minority in the
EAT suggested that the reason for the detriment was not the level of demand
itself, but the failure of the employer to meet the business needs in a way
which was more equitable to part time workers.

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