[holding answer 15 May 2007]: I have been asked to reply.
Immigrants arriving at Dover will already have passed through the juxtaposed border control in Continental Europe. If the arriving passengers are residents of a country where pre-entry screening is required then they will already have been screened for tuberculosis.
Illegal entrants who are apprehended at Dover may be detained at a police station and would be referred for a medical examination if necessary. If detained at an immigration removal centre they are required under the Detention Centre Rules 2001 to be given a medical examination within 24 hours of admission subject to their consent.