Dozens of sham marriages have been stopped after immigration officers monitored Leeds city centre register office for just one month.
Bursting into two weddings to stop men who had arranged married to dodge immigration laws, the UK Border Agency's special investigation team managed to stop 70 sham marriages altogether.
The services were filmed by the BBC's Inside Out Yorkshire programme, shown on 13 February, which followed the officers as they closely monitored the register office at Leeds Town Hall.
In the first operation, officers swooped on a wedding between a French bride and an Indian groom whose leave to remain in the UK had been revoked.
A second wedding between a Pakistani man and a Lithuanian woman was also halted.
Border Agency staff spent four weeks interviewing everyone getting married at Leeds register office.
In that period alone, they estimate they prevented 70 sham weddings from going ahead.
Detective Inspector Adrian Watkins, from the UK Border Agency, said: "Certainly since we started looking at these last March, there's been an increase and they've been brought to our attention on a more regular basis, probably because the registrars themselves are more aware of the problem.
"We've done an awful lot of work leading up to the operation, intelligence work.
"We've also got excellent co-operation with the registrars.
"It's the registrars themselves who inform us after asking certain questions which raise their suspicions."
Church officials also have to look closely at who is getting married.
The rector of Leeds Parish Church Canon Tony Bundock said: "Because of some of the abuses that did take place a few years ago, we're now required to check that the address that they've given us is genuine by actually visiting them, going to both houses, both the bride and the groom.
"Also we're required to check their identity by seeing some documentary evidence that proves that they are who they say they are."
In January, John Magumba, a Church of England vicar, was jailed for two and a half years today after carrying out dozens of sham marriages which allowed illegal immigrants to live in the UK.
Magumba was taking so many weddings involving foreign nationals his diocese put him in charge of a special working party on how to handle marriages for foreigners - and how to spot sham weddings.
The documentary will be shown at 7.30pm on BBC1 in the Yorkshire area and on the BBC iPlayer.