A novel high-frequency lossy uniform transmission line model is presented in this study. Novel features include a compactness of form and a level of simplicity that confers enhanced simulation efficiency in practical applications. Although specifically developed to target implementation in generic versions of SPICE, the compact high-frequency model can be implemented using only four lines of netlist syntax in the case of circuit simulators that offer native Laplace equation support. Featuring a broadband frequency response characteristic that is defined by only four parameters, the compact HF model is based on a novel theoretical approach that elegantly connects the four model parameters to physical line parameters using only elementary line characterisation data. Important and perhaps surprising differences between the new model theory and classical textbook theory are highlighted and discussed. The lessons learned are then incorporated into a second hybrid model featuring a higher level of complexity that combines both new and classical theoretical approaches into a single set of model equations that are better suited for atypically small controlled impedance structures such as silicon interposers and on-chip clock and data distribution schemes.