Type of motorbike licence you will need
Unless you are specifically looking to purchase a lower power motocross bike, you will likely require an A2 or unrestricted A Motorcycle Licence since most motocross models tend to be towards the higher end of the power spectrum.
Engines larger than 125cc but below 500cc require an A2 Licence – for which you must either have held an A1 Licence for 2 years and taken an additional practical test to qualify for, or you need to be a minimum of 19 years old and take a Direct Access route which includes a CBT, theory test and practical tests.
For motocross motorcycles larger than 500cc an unrestricted A Motorcycle Licence is needed. These can be attained by having had an A2 licence for 2 years and taking an additional practical test, or being a minimum of 24 years old and taking a Direct Access course which includes a CBT, theory test and practical tests.