Since April 2004 there have been new legal limits on the extent to which an agency can require a company to pay a fee, if they wish to recruit you to a permanent post in their company. An agency can still charge the employer, but only where you transfer from the agency to the employer's permanent staff within either:
whichever ends later. If the transfer takes place after this time, the agency will not be able to charge your employer a 'temp to perm' fee.