You need a licence for a VHF on a boat and a different one for the operator. Here you can find out how to apply and which licenses are relevant for you.
The vessel’s licence is like a car tax disc, but it is also the key to obtaining an MMSI number, which will uniquely identify your vessel. You can obtain an application form for a ship’s radio OFCOM. You can also obtain an application form for a transportable licence from the same place.
See a full index of OFCOM Radio communications documents.
The user requires an operator’s licence and two different types are available. For VHF only the SRC (Short Range Certificate) is available. VHF marine radio operation itself is fairly straightforward and training, covering radio etiquette and procedures, takes one day. It also teaches about the advent of digital selective calling (DSC) functions and new emergency procedures.
For other communications the LRC (Long-Range Certificate) is required. This covers procedures, such as setting up an HF call, and takes three or four days.