Molecular mechanics (MM) force fields for biomolecular simulations have been under continuous development for many years. In traditional transferable force fields, every atom in a molecule is assigned a type based on its atomic number, bonding and local chemical environment. The atom type then dictates the parameters that are used to model that atom's interactions. The force field parameters for each atom type are stored as a library, which is built by carefully reproducing the experimental or quantum mechanical properties of a benchmark set of small molecules. Due to the infeasibility of accurately parameterizing all of chemical space, a balance must be made between the size of the library and potential inaccuracy due to transferring parameters to molecules outside the fitting set. In many cases, it is acknowledged that transferable force fields are not sufficiently accurate. When building force fields for small molecules, the atomic charges are usually assigned in a system-specific or "bespoke" manner, using methods such as RESP, CM1, or AM1-BCC. This is because it is well-known that atomic charges polarize in response to their chemical environment (for example, the presence of electron donating or withdrawing groups). Bespoke charges are usually assumed to be compatible with the fixed Lennard-Jones parameters of the force field, although these themselves have also been shown to be dependent on the local environment of the atom. Although proteins must also experience polarization effects in both the charges and Lennard-Jones parameters, protein force field parameters have always, to date, been assigned from a transferable library. This leads to an inconsistency in the parametrization strategy used for protein force fields and bespoke small molecule force fields. This is potentially problematic when studying properties that depend on the electrostatic potentials of proteins, such as their interactions with small molecules, and there is no clear way around this using traditional force field fitting methods.