child visa with unknown father

My wife and her child applying to settle in the UK. Does anyone know if there are likely to be and issues with the fact that I am not the biological father of her child and that the father is registered as being unknown?

As the child's visa sponsor there shouldn't be an issue.

The larger issue is the mother would have to prove that she has either sole legal & physical custody or can prove 'Sole Responsibility' for the child.

If there is no court order for custody and there is a father listed on the birth certificate then there will need to be a notarised letter from the listed father granting permission and approving of the visa application.

This will also need to be addressed with the child's passport application (if it hasn't been done already).

The childs father is not on the birth certificate only the mother. The child already has a passport and has used it to visit the UK last year. It sounds like there shouldn't be a problem.

It sounds like she will just need to prove Sole Responsibility.  If the father hasn't been involved in the child's life...it shouldn't be too hard...just adds a bit of extra work for your wife.

By proving sole responsibility... do you just mean showing all the paper work ie the birth certificate and a governmental letter form DCF stating that the biological father is unknown? Or does she also need to do more than that? Anyone here have this experience?

I don't have any personal experience with it (I got notarized permission from the father, even though he is not listed on the birth certificate) but the link that WebyJ provided for you explains exactly what is taken into consideration to prove sole responsibility.  Your wife would need to make sure she can do that.  Personally I would provide more than the birth certificate (perhaps a letter from the child's doctor and bank statements/receipts showing I was the only one financially supporting the child, along with a detailed letter explaining the situation with the father)...but I've never seen a clear breakdown of what is expected.

Okay... so along w/ the b certificate, and DCF paper work...  she just needs to show his Dr appointments and childcare stuff etc etc? That should be okay... but in the world of visas we're learning just how much we dont know!