If you are doing work different from that of a worker of the opposite sex in the same establishment, but the different jobs have been rated as equivalent under a job evaluation scheme, you are entitled to equal pay.
There has to be someone of the opposite sex, with whom you can compare (a 'comparator').
Differences such as payment for extra responsibilities are permitted, providing the differences are not based on the sex of the worker.
Claims for equal pay for work rated as equivalent are made to employment tribunals within the specified time limits.