OK, she needs to look at this link, particularly down at the bottom of the pages.
http://www.direct.gov.uk/en/Employment/Employees/Pay/DG_10026695
'told they can no longer employ her' could cover a multitude of sins and she needs to establish what has happened to the business. Is it insolvent? If so, there are mechanisms by which an employee can get up to 8 weeks pay back from a Government fund established for this purpose. The link tells you how to do it.
If the business is still trading and they have merely decided they don't want her any more, if she had more than 12 months continuous service, even as a part-timer, she could take the matter to an Employment Tribunal for unfair dismissal - especially if they just said 'bye - we don't want to see you again', without paying her notice pay and holiday pay.
If the business is still trading and she doesn't have minimum time as an employee, the route is through the Small Claims Court to make a civil claim for back wages.