Three quarters of reports about alleged sham marriages result in no action being taken, according to a survey of registrars.
Registrars who send details to the Home Office of suspect marriages rarely receive any feedback on whether the allegation was investigated.
Results from an online survey of registrars showed that of 879 reports that a planned marriage might be bogus, registrars knew of action being taken to investigate or stop the wedding in only 213 cases.