Training belongs to the person who completes the study, no matter who pays for it.
Even if an employee leaves just after their employer has spent £3000 on qualifications for them, the employee takes that qualification with them to their next employer.
In recognition of the considerable cost to achieve some qualifications, employers may wish to consider using a pre-training agreement. This enables employers to recover a proportion of training costs from the employee should they leave within set timescales.
A template agreement can be downloaded for your use. The timescales and proportions of fees listed are suggestions: it is up to each employer and employee to negotiate an agreement appropriate to the business and individual circumstances.