How long approximately does a green card application take?

It depends. In most situations, with full and efficient cooperation of our clients, we can have the petitions filed within 14 days after all documents are in.

Usually about 9-12 months from start to consular interview. You will have to document domicile intent for yourself.

About a year or year and a half.

Generally, this process will take 6-12 months to complete. Expect 3-6 months on stateside processing and the remaining period for processing by the National Visa Center and the US Consulate. The consulate in London is generally fairly prompt with its processing of approved petitions so you should not expect much in the way of delays one the approved petition makes its way overseas.

If you are a US citizen residing permanently abroad in the UK for at least the past 6 months (within the jurisdiction of the requisite US Consular District) along with your alien spouse, you and she may qualify to "consular process" (as opposed to "adjust status" in the US) for her immigrant visa and her I-551 "green card" packet which is presented to the admitting officer at the US point-of-entry (which may be what you have already initiated when you state that you have "started the application for her visa".) The length of that process can best be determined by consulting with your US Consular officer in the UK as to the length of his/her particular consulate's average processing time for immigrant visas (IV). In most cases, the entire process can be done in less than six months, often faster if there is not a significant IV backlog at the particular Consulate involved. In contrast, adjustment of status for your spouse once she comes to the US (i.e. on a K-3 Visa) can take well over one year and, occasionally, longer before actual receipt of her initial green card.