Immigrationboards.com

I arrived in the uk in 1971, subsequently in my original passport I received a stamp which states "the time limit on the holder's leave to enter the United Kingdom is hereby removed" and a supporting Home Office letter, which formally states that I am free to remain permanently in the UK. It also states that if I leave I will need to return within 2 years. I contacted the Home Office recently and have been told that my file has been destroyed as it's been such a long time ago.

I have never travelled since I arrived in the UK and now that I have retired, I want to visit my home country. I have read that I do not need to transfer my stamp to my new passport, as long as I carry my old passport (with my indefinite leave to remain stamp) and my new passport.

As it's the first time travelling in over 40 years, I'm a bit anxious about the whole trip and I wanted to get an idea about what questions I will be asked by the immigration officer on my return to the UK, when I present my old passport and supporting Home office letter. Will I need to provide any other proof on my immigration status and evidence that I have not remained outside the UK for more than 2 years?

Not an issue, you can carry your old passport containing ILR stamp with your current passport and enter the UK without any issues.

At immigration desk, you should not have any issues. They will normally ask you how long have you been away.

The Exit/Re-Entry stamps in your passport will prove whether you have been out of UK for more than 2 years or not.

Thank you Lynxukauq, I think I need to stop worrying and just think about my holiday

I can confirm having used two passports to go on a holiday a couple of months ago. On entry, just show both the passports stating which one has the visa. For me, the officer immediately returned the new, valid passport and asked a few questions about what I did, why I went out of UK, etc while looking at the old passport. Normal stuff. Enjoy your holiday

One of the reasons why I was concerned, is because on the UKBA website, I read that if you can prove that you are entitled to live in the UK, the immigration officer will put a date stamp in your new passport, you must then make an application asking to issue a BRP.

I'm guessing that they are referring to a situation where you don't have your old passport with a stamp, however you provide some other unofficial document at the border to help prove your immigration status.