John, they want people to come under this rule as soon as possible. There is no benefit to either side for a transition period. Cold turkey. One day 18, next day BAM 21.
Sorry I really do not think it is anything like that simple!
In particular, a fiancé(e) (or proposed civil partner) might have already been issued .... to a 18, 19 or 20 year old. The visa holder might already be in the UK! Or arriving soon. The marriage (or CP registration) might be planned for December or later. Are you really saying that it is OK that such visa holder goes into some sort of limbo? Surely, having issued the fiancé(e) (or proposed civil partner) visa, the Government needs to allow the spouse (or CP) visa to be issued ..... even to a 18, 19 or 20 yo.
So rather than "There is no benefit to either side for a transition period.", I think there is a definite need to have transitional arrangements in place, to stop people falling into gaps in the system.
Indeed I would go so far as to say this. After the issue of a fiancé(e) (or proposed civil partner visa to an 18, 19 or 20 yo, if the Government refuses to allow such visa to be converted into a spouse (or CP) visa ..... that will result in very speedy legal action ... and the Government will yet again end up with egg on its face.
Also, as regards :-
The age at which someone can apply for a marriage visa will increase from 18 to 21 from the end of this month, the Government announced today.
From 27 November both parties in a marriage will have to be 21 before a marriage visa can be issued.
-: which is it? Is the applicable word "apply" or is it "issued"?
Or is it really being suggested that someone could apply for a visa just before 27th November, and pay the application fee, with no realistic hope that they will get anything for their money?