According to TES FAQ, the DfES number can be found on a teacher's QTS certificate. This number can also be accessed by contacting Capita, the company in the United Kingdom that focuses on teachers' pension arrangements.
A DfES number, also known as the Department of Education and Skills number, is provided to every teacher in the United Kingdom. It is known by other titles as well, including the DES, DfEE and GTC number, according to TES FAQ.
A DfES number typically looks like this: 01/23456. It contains the individual and unique number for the teacher in question. If the reference number is unable to be found, then Capita can be contacted by phone or email. This company has a record of all UK teacher numbers.
In the past, teachers in the UK had to join the GTC, the General Teaching Council, which maintained a register of all teachers in England. The GTC focused on maintaining a register of teachers, regulating the teaching profession, and providing advice to the government and other agencies working with teaching or learning policies, Wikipedia states. This body has now been disbanded, so teachers are not required to join any professional group, according to TES FAQ.