1. Apparatus for real time control of glucose in a human or an animal, the apparatus comprising: a sensor providing a time series of measurements of glucose level, said measurements being indicative of an inferred level of said glucose in a part of said human or animal, a processor which is adapted to perform the following steps: calculate a first estimate of said inferred glucose level from said measured glucose level using a first glucoregulatory system model, calculate a second estimate of said inferred glucose level from said measured glucose level using a second glucoregulatory system model with said second system model being a variation of said first system model, and predict a combined estimate of the inferred glucose level based on a combination of the first and second estimates, wherein the processor is a state estimator and is adapted to define a state vector for each model, the state vector comprising a set of variables each having an associated uncertainty, the set of variables including a variable representing an unexplained change in glucose level with each model having a different standard deviation in the unexplained change in glucose level; wherein the first and second glucoregulatory models each comprise a sub-model of glucose kinetics in the blood of said human or animal, a sub-model of interstitial glucose kinetics, a sub-model of insulin absorption, a sub-model of insulin action and a sub-model of gut absorption; and wherein the state vector includes the following states 
 x k =( q 1ƒ,k ,q 2ƒ,k u S,k ,F k ,q 3ƒ,k ) T where q 1ƒ,k , q 2ƒ,k , and q 3ƒ,k represent glucose amounts in the accessible, non-accessible, and interstitial compartments excluding the contribution from meals, u s,k is the unexplained glucose influx and F k is glucose availability, and a dispenser that delivers a specified amount of medication to a user in response to a command from the processor based on the predicted combined estimate of the inferred glucose level.