There are many types of prison with the UK, both private and publicly owned and these are best defined by the nature of the prisoners they keep.
Beyond the obvious split between male, female and juvenile, prisoners are categories according to the risk they represent to society and to each other. There are also a split between Local Prisons and Dispersal Prisons. A Local Prison is where you will be sent initially and where the assessment of you will take place. As its name suggest, a Local prison will be local to the area of the court where your trial is held. Depending on the length of your sentence you may spend all your time at a local prison, but if your sentence is for a longer duration (over 4 years) you may be sent to Dispersal Prison where you will serve your sentence. It is as broad as it is long which type of prison is best, there is little to choose between them in terms of the regime they operate or the work/education opportunity they offer
All prisoners are given a category which sets out how the prison system will handle you. At the most serious end for male prisoners are Category A prisoners. These people are defined as being “Those whose escape would be highly dangerous to the public or national security. Offences that may result in consideration for Category A or Restricted Status include: , Attempted murder, Manslaughter, Wounding with intent, Rape, Indecent assault, Robbery or conspiracy to rob (with firearms), Firearms offences, Importing or supplying Class A controlled drug, Possessing or supplying explosives, Offences connected with terrorism and Offences under the Official Secrets Act”. Category A prisoners are further segregated into Standard Risk, High Risk, and Exceptional Risk, based on their likelihood of escaping.
Unless you are a Category A prisoner, when you are first committed to prison you will automatically be categorised as a Category B prisoner who are defined as “Those who do not require maximum security, but for whom escape needs to be made very difficult like”. If you are being held on remand you will be set as a Cat B prisoner. After some time in prison you may be set as a lower profile prisoner and will be categorised as Category C who are defined as “Those who cannot be trusted in open conditions but who are unlikely to try to escape”. Finally there are Category D prisoners who are held in open prisons which have a more relaxed regime. Category D prisoners are defines as “Those who can be reasonably trusted not to try to escape, and are given the privilege of an open prison.” It take some time to progress through the various categories; if it is your first offence and it is was a non violent or drug related crime, such as fraud, you may be categories as a Cat D within a month of being sent to prison. The speed of progression depends on how you have reacted to the prison rules and regulations and how you have behaved whilst in custody. However while you are in prison your category will be regularly reviewed and towards the end of your sentence you may well be re-categorised at a lower risk level. If your sentence is for a relatively short period , say under 2 years, the prison may not progress you down the risk categories and you will stay as a Cat B for the entire time; if this is happening to you speak to your lawyer for advice as to how to proceed.