No job for Mr Tiddles?

What I want to know is whether it would get expenses or any other allowances?

Mr. Gordon Prentice: To ask the hon. Member for North Devon, representing the House of Commons Commission if the House of Commons Commission will consider the merits of providing a resident cat.

Nick Harvey: The Commission has no plans to introduce a cat. The House Service includes a qualified pest controller, who monitors and controls pests on the parliamentary estate using humane and effective methods. In addition, an independent expert is employed to audit and advise on pest control, and inspections of catering areas are undertaken by the local council. The clear advice we have is that all effective measures possible are being taken, but that in a building such as the Palace, pests such as mice can only be controlled rather than eradicated.

Hansard

All seems pretty clear, the House already has a "qualified pest controller", if a cat wants the job it will have to at least have a C-Grade GCSE in Ratting*.
* Qualification coming to a Comp near you soon