I assume as a tourist a Thai would need six months validity, but with this visa does she count as a resident and would therefore not have any problems getting back in?

She should be fine to get back in. When she checks in at the airport, make sure the desk clerk is aware she has a residents visa.

ILR is indefinite and wont lapse simply because the passport the stamp is in has expired, or is close to expiring. As long as the passport is still valid then she can use it to re-enter the UK.

However, it will probably be easier if she renews her passport whilst still in LOS as doing so in the UK will mean a trip to the RTE in Kensington.

She then simply carries both old and new passports and shows both to UK immigration when she arrives (and to the airline when checking in).

Or she could pay the exorbitant fee introduced by Labour to transfer the ILR stamp to her new passport!

But: You say "going back" and "getting back in."

How long has she been out of the UK?

If more than two years then the ILR will have lapsed and she will need to apply for a new visa in the relevant category.

Does she live in the UK and is returning having been in Thailand for a holiday/visit; or is she now resident in Thailand and going to the UK for a visit?

If the latter and it becomes apparent to the Immigration Officer at her port of entry to the UK that she is no longer resident in the UK and using her ILR to gain entry for a visit then her ILR will be canceled and she will probably be permitted entry as a visitor instead.

Thanks both for the replies. However the girl at the British Embassy has since told her that she WILL need to get a new passport, which conflicts with what you are saying, but may not be accurate. It seems like getting a new passport will be the sensible thing to do. It's not worth the risk.

7by7: She meets all the requirements listed on the British Government website so should be fine. She's only been away for just over one year, and while she has been living and working (paid by cash) here in Thailand, I can't see anything to suggest that would be a problem as long as it has been for less than two years.

She should be OK, but may be questioned at UK immigration as to her intentions. If she has any documents to show she is returning to resume residence, rather than just visit, then she should carry them in her hand luggage. See IMMIGRATION DIRECTORATES' INSTRUCTIONS, CHAPTER 1 SECTION 3.

She could apply for a returning resident's visa in Bangkok, but it's not compulsory and as it costs 11825baht (£215), I don't personally think it's worth it just to forestall a few questions on arrival in the UK.

Forget the visa here we are talking about the passport she must renew this before travel.

Airline check in have strict instructions on passport and travel she must have a valid passport for entering the UK with 6 months or more on this.

seems more complex than it used to be. i just took my old and new passports with me and at heathrow they stamped it with the indefinate leave and wrote as per previous passport. they had 3 goes at is as they got the stamp upside down a couple of time s and that is a no no.

She would have to carry both one showing she has a valid Passport for travel the other showing a valid visa for travel.

It used to be that a UK ILR holder with a new passport would simply present both to an immigration officer the next time they entered the UK and they would have a new ILR stamp placed in the new passport.

Then this Labour government decided to charge an exorbitant fee for transferring the ILR stamp, so IO's are no longer able to do this and the ILR holder has to make an application, either to he UKBA if in the UK or a British embassy if outside, and pay this fee to have their ILR stamp transferred to a new passport.

However, ILR is indefinite and, unless it has lapsed for some reason, is still valid even if the passport the stamp is in has expired. So the government cannot legally make one transfer the stamp and carrying both old and new passports is both legal and acceptable to immigration.

So, when the OP's friend receives her new passport there is no need to transfer the stamp, she simply carries both and shows both whenever necessary.