Ltd Company shares and employees

The company want's to retain an important member of staff but can't afford to offer a pay rise. It is looking at setting up an EMI and paying the member via dividends (after paying the National Minimum Wage as salary).
If the dividends paid on the shares issued are in the region of £40K per annum - what are the consequences when the employee leaves and the shares need to be bought back? Are there any other problems to consider?
Thanks- your comments are gratefully appreciated.
Justine