Need advice about my travel by using an official passport

[Anatureth]

Dear all,

I am a Thai student, living in UK with Tier-4 visa.I came to London by using my national (normal) passport.

I am a government officer so I also have an official passport of Thailand.
On 13-14 February 2017, I am invited to join the meeting at Geneva, Switzerland.I have contacted the Switzerland embassy, they said that Thai official passport holders do not require a visa for Switzerland when travelling for tourist/ visit purposes of up to 90 days.

However, I have another point that I need your clarification.
Since I used my normal (national) passport to enter London for my study last month, is it OK if I will use my official passport and my BRP to show the immigration officer about my leaving for Geneva and re-entering to London?
Would it be necessary to show both passports to the immigration officer for my travel?

Thank you very much.

[sah10406]

Since I used my normal (national) passport to enter London for my study last month, is it OK if I will use my official passport and my BRP to show the immigration officer about my leaving for Geneva and re-entering to London?
Would it be necessary to show both passports to the immigration officer for my travel?

Why not just show your national passport when you re-enter the UK? It seems very complicated to bring this other passport into the picture, when there is no reason to do so.

[Anatureth]

Thank you very much for your help.
I have replied you few days ago. But I am wondering that there might be some problem with the internet.

I will travel tomorrow. Perhaps I will first try to use my official passport. If the immigration is alright, it must be not any problem.

I will update you again.
Thanks

[CR001]

You must re-enter the UK on the passport that holds your student visa.

Have you declared this official passport with HO in any previous applications?