Below are the two main modelling institutions in the UK. Click on the relevant image to go to their website.

 
British Model Flying Association
The BMFA is the National Governing Body for the sport of model flying. Its aims are to promote, protect, organise and encourage model flying within the UK. Typically there are around 780 affiliated clubs and a combined membership of over 36,000 members, all of whom have entered a partnership to ensure that model fliers have a voice and their rights are recognised by the authorities. Membership bring many benefits including 3rd party insurance of up to 5 million.
Large Model Association
The Large Model Association (LMA) is based in the UK. Its members are interested in the designing, building and flying of large model aircraft.