If you currently have a child that is under 18 who is either a British citizen or is settled in UK, you may be eligible to apply to come to the UK, or remain in the UK if you are already here.  You may also qualify for leave to remain if you and your child are in UK, and your child has lived here for 7 years (even if they are not currently a British national or has indefinite leave to remain).

It is important to note that in all cases, you must not be eligible for a spouse or partner visa, as you must apply via the 'partner route' if your spouse/partner is a British citizen or is settled in the UK. - You cannot apply directly via the parent route if this is the case.

So, presuming you are not eligible to apply as a spouse or partner, you can apply for a visa as a parent of a British Child to come to the UK if you:

1. Meet the suitability requirements in Section S-EC Appendix FM; and

2. Meet all the legal requirements below:

Relationship Requirement

You must be over 18, and your child must currently be:

• Under 18;
• Living in UK; and
• A British Citizen or settled in UK.

You must also have “sole parental responsibility” for the child. or if you have shared responsibility, the other parent must be:

• A British Citizen or settled in UK;
• Not your partner

You must provide evidence that:

• You have sole parental responsibility for your child or you have access rights to your child, 
• You are taking an active role in the child’s upbringing and will continue to do so.
  
  

Financial Requirement

You must be able to evidence that you will be able to adequately maintain and accommodate yourself and your child in the UK without recourse to public funds. You must also evidence that you will have adequate accommodation available in the UK, without recourse to public funds, for the family, which the family own or occupy exclusively.

English language requirement

Unless you are are a national of a majority English speaking country e.g. USA or Australia, you must be able to evidence that you have good knowledge of english by one of the following:

• Pass an approved English language test in speaking and listening at a minimum level A1 of CEFR; or
• Have an academic qualification equivalent to a Bachelor’s or Master’s degree or PhD in the UK, which was taught in English
  

Applying to Remain in the UK

If you are already in the UK and want to switch to or extend your visa in this category, you can apply for leave to remain as a parent of a child in the UK if you are currently in the UK on a visa which is valid for more than 6 months (not a visitor or tourist visa) and are able to meet the requirements.  If you cannot meet the requirements, you may still be able to apply (Refer to Paragraph Ex1 below)

Children over 18

If your child is now over 18, you are still eligible to apply for an extension of the visa if your child was not 18 at the time you were first granted the visa in this category, and they are not now leading an independent life.

Paragraph Ex1

Paragraph EX 1 of Appendix FM of the immigration rules gives an exception to rules relating to family members of British or settled persons in the UK. EX 1 can be applied to leave to remain applications where an individual has a genuine and subsisting parental relationship with a child who:

• Is under 18 years old ; 
• Is currently in the UK;
• Is a British Citizen/settled in the UK, or has lived in the UK continuously for at least the 7 years prior to the date of making the application;
• It would be unreasonable to expect the child to leave the UK

Also note that if EX1 does apply to your case, you are exempt from meeting the English language and financial requirements.

Grant of Visa - 5 Year or 10 Year Route

If you meet all the requirements, the visa will be granted for a period of 2 and a half years, and you will be eligible to apply for indefinite leave to remain (ILR) after a continuous period of at least 5 years in the UK on the parent visa. So if you are granted this visa for the first time, you will need to apply for an extension, and after 5 years you will be able to apply for ILR.

If however you applied under the EX1 exception, you will be put on the 10 year parent route. So this would mean, you would need to make 3 further extensions after the first time the visa is granted to qualify for ILR.