This is a very vital issue, in view of the fact that the easiest way to get permanent residency in the UK is through civil partnerships and/or marriages.
The revised Immigration Act of 2014 has made revisions to the requirements for notice. The stipulation to provide notice of a planned marriage or civil union has been lengthened to 28 days from 15 days by the Immigration Act. This change refers to everybody living in Wales and England, no matter where they might be from or their nationalities. Information must be made to a Registrar by the two people on their own and in person, and they will be needed to give specified proof of their nationality. This is unlike what previously obtained where the registration office/Registrar had to just only be comfortable of their nationality. If an intending couple did not possess the appropriate papers and documents, it would be quite hard to be married or create a civil partnership while being resident inside the United Kingdom.

The registration officer has now been given the power and authority through new powers of investigation to inform the Home Secretary if one of the intending parties/couples in the planned marriage/civil union is a non-EEA citizen. Once the state secretary has been duely informed, she would have up to a maximum of 28 days to make up her mind on if or not to commence a deeper scrutiny of the intended union. If she decides to choose not to scrutinize further, she would have to inform the Registrar and the intending couple who could now go ahead to get married and/or create a civil union or partnership.

On the other hand, if the state secretary has sufficient evidence or facts or proofs or suspicion that the intended marriage or civil union is not real but a fake, then she can proceed to start an enquiry which would go further beyond the usual period of notice of 28 days up to as much as 70 days. During this extended period of notice of 70 days, there would be visits to their homes and/or questions and interviews.
The sorts of issues that can lead to one being suspicious or curious about the intended marriage and/or civil union would be if one or both of the intending parties:
Is a citizen from a country or nation that has a very high probability of being involved in sham marriages and sham civil unions;

Has a visa or residency documents which are related in sham marriage situations;
Has no status on immigration or possesses a leave which is going to soon be exhausted;
Has before now sponsored another person to come into or stay back in the United Kingdom.

Another important revision is the stoppage of the exclusion from civil preliminaries for non-EEA citizens who are getting married in the Church of England.
Registering officials are now required as part of their duties to make reports of suspicions of any likely fake marriages or civil unions.