Provision for reckoning in respect of a person to whom the regulations apply any service in employment or as the holder of an office (other than service in respect of which benefits are payable under the regulations) as service in respect of which such benefits are payable, either unconditionally or subject to such conditions as may be prescribed by the regulations and either as respects the whole of the service or as respects such fraction thereof as may be so prescribed.

In this paragraph “employment” includes engagement in any service.