"It is, of course, impossible to lay down any hard and fast rule as to the amount by which the sentence upon a large scale informer should be reduced by reason of the assistance which he gives to the police. It scarcely needs stating, and indeed this is the way that Mr Pollard approached the problem, that the court will first turn to the offences which the informer has admitted to assess their gravity and their number. That should enable the court to arrive at what might be called the starting figure. For instance, if, as so often is the case, the offences are robberies and have involved the carrying of firearms or their use, the use of disguises, the making of detailed plans, or if they have involved attacks upon security guards or the like, the court will apply the guidelines laid down in well-known case of Turner [reference given] and will be able to arrive at an approximate figure, sometimes in the region of 18 years' imprisonment or more. On the other hand, the starting figure in the cases of multiple burglaries where no violence has been used will usually be less. The figure there will then, once again, depend upon the number of cases involved and whether the property attacked was private dwelling-houses or business premises, and no doubt other features as well.