i ask DVLA the same question here is the copy of the email i recieved back. Hope this Helps
Subject: RE: Towing under new licence categoriesThank you for your email about towing trailers.
Please find below information you require, if you are a holder of a Category B licence.
I should start by explaining, if you are a holder of a category B licence you are able to tow the following combinations:
If your car weighs less then 3.5 tonnes MAM you are able to drive a combination weight of 3.5 tonnes (i.e. car of 2.5 tonnes and a trailer of 1 tonne). In this instance the laden weight of the trailer must not exceed the weight of the towing vehicle.
If your car weights exactly 3.5 tonnes MAM you are able to tow a small trailer of 750kgs.
If you would like to tow a larger trailer you will need to contact the Driving Standards Agency with a view of booking a test for category B+E. Their contact details are given below.
Tel Numbers: 0870 0101 372 or 0115 901 2500
Enquiries - customer.services@dsa.gsi.gov.uk
Test bookings - bookings.dsa@prima.net
Website address -
www.driving-tests.co.ukPlease note, if you are a holder of a full car licence you will automatically have provisional entitlement for category B+E.