motocross bikes road legal?

[Sam P]

i have a standard motocross bike. no indicators lights ect but i would like to be able to ride it on the road in the day time. i live in england. what do i need to add to the bike to make it road legal? i saw a motocross bike rider who just added a number plate to the back when he rode it on the road. is this legal in just the daytime? thankyou, sam