Wikipedia:DR10

A DR10 is a United Kingdom motoring endorsement issued by the Driver and Vehicle Licensing Agency (DVLA) and UK Police which means driving or attempting to drive with a blood alcohol level above the allowable limit. Following an arrest for a DR10 one can expect a ban from driving and a fine. In more serious cases, a Community Order, or a prison term of up to 6 months may be issued.

Drunk driving
In the UK drunk driving is classified as driving a motor vehicle whilst over 35 micrograms of alcohol per 100 milliliters of breath (or 80 milligrams of alcohol per 100 milliliters of blood). The request to take a breathalyzer test must be made by a police officer in uniform, but can only be made if one of the following situations apply:


 * 1) the police officer has reasonable cause to suspect that the driver has committed, or is committing a moving traffic offence, or
 * if, having stopped, an officer has reasonable cause to suspect that the person driving/attempting to drive/in charge of the vehicle has consumed alcohol, or
 * 1) the police officer has reasonable cause to believe that the person driving/attempting to drive/in charge of a motor vehicle which was involved in an accident.

Detecting circumstances relating to a DR10
After the officer has established contact with the suspect and suspects a drink driving offence, the officer will ask for a specimen of breath at the road side to verify if the suspect has exceeded the prescribed limit. This test is not sufficiently accurate to be used in court. If the road side reading is above 35 micrograms, the suspect is arrested and taken to the police station.

At the police station the accused will be asked to provide two specimens of breath for analysis (using approved evidential instruments such as the Intoximeter EC/IR; Lion Intoxilyzer; or Camic Datamaster). If the two readings differ, the police rely on the lower reading. If the reading is over the prescribed limit, but is equal to or below 39 micrograms, a caution is given. If the measurement is between 40 and 50 micrograms, the accused must be offered a blood or urine measurement. While the accused has the right to the alternative measurement, it is for the police to decide whether a blood or urine test is appropriate in each case. Blood measurement is performed by the police surgeon. If the reading is over 80 micrograms then the suspect will be charged with a drink-driving offence.

The penalty can variously be a fine, disqualification from driving, unpaid community work, or a prison sentence. If the circumstances leading to the arrest included careless, dangerous or bad driving; or if a new driver (licensed for less than 2 years), then an extended re-test can be ordered. In this case, at the end of the disqualification period, a provisional licence must be obtained and theory and practical tests passed. Only a court has the power to impose these penalties.