Since your driving license is issued in Nepal, it will not be valid in UK. Only the license issued in EEA/EU nations it will be valid in UK. Driving license issued in some other countries indicated as non-community countries will be valid for one year in UK. In your case, when you are in UK, you’ll have to apply for provisional driving license. After you apply for provisional driving license, you’ll need to pass a driving test to obtain a license. To be eligible to apply for provisional driving license and take a driving test, you must be in UK for more than 6 months. Students like you from India, Pakistan, Bangladesh, Malaysia, China, Russia, Nigeria, Egypt, Thailand etc will also have to obtain a driving license before they can drive in UK.

You can actually apply for an International Driving License.  You can apply for the International Driving License in your own country before you travel to the UK. Should you want to rent a car, drive your own etc, you will have to have either a valid UK license, or valid International License. I'd suggest that you get an International License so you're covered for the first 6 months in the UK.