You can apply to come to the UK in this category if you can show that:
you are a Commonwealth citizen;
you are aged 17 or over;
you are able to work and you plan to work in the UK; and
you can adequately support and accommodate yourself and your dependants without help from public funds - the Rights and responsibilities section explains what public funds are.
You must also show that at least 1 of your grandparents was born in the UK (including the Channel Islands and the Isle of Man) or before 31 March 1922 in what is now the Republic of Ireland or on a British-registered ship or aircraft.
You can claim ancestry if your relationship to the relevant grandparent is in the legitimate or illegitimate line.
You cannot claim UK ancestry through step-parents, but you can apply if you or your parent (through whom you are claiming ancestry) are adopted. You must show evidence of the legal adoption with your application form.