She has been a lecturer for 11 years and is currently employed on an indefinite variable contract, which means that while she is a permanent employee, her hours have varied from 200 to 900 a year.
"On many occasions, I have ended up doing the same or a very similar job to full-timers on what works out as lower pay," she says.
"You stay on the very bottom of the scale. In fact, I am still paid at the same rate as somebody who is newly qualified and newly employed.
"I constantly hear the term 'only a part-timer' used in the college, which is definitely a value judgment. It seems to imply that you're just working for pin money."
With help from the lecturers' union Natfhe, Ms Lewis organised a meeting of part-time lecturers which later led to the creation of a part-time workers'
The group managed to negotiate a new contract for part-time lecturers. The deal now guarantees teaching staff a minimum number of hours and has helped to clarify their duties and responsibilities.
Other colleges and unions have since expressed an interest in the new contract and Ms Lewis has addressed the Trades Union Congress on this issue.