The radio sources 3C 382, 3C 452, and 3C 465 have been mapped with the Cambridge One-Mile telescope at 2.7 and 5 GHz and with the Five-Kilometre telescope at 5 GHz. Each source has a central component less than 2'' arc in diameter which is coincident with the nucleus of a galaxy, and outer components of considerable complexity. The extended components of 3C 452 and 3C 465 are significantly polarized. The observations are discussed in terms of different models for extended radio sources. None of the simple models can adequately account for all the observed features, but modifications of these models are proposed to obtain qualitative agreement with the observations. Several correlations between the physical propenties of different extended sources are proposed. (auth)