IRA to Roth IRA conversion

Hi, I live in the UK am a dual UK/US citizen, have a few questions about consolidating my US pensions.

At the moment I have a 401k and an IRA account and plan to do a direct rollover of the 401k into the IRA, I've already checked for the  US and there is no tax liability, taxes come later on withdraw. Question is are there any UK tax implications when doing this and/or is there any reporting required on a UK tax return?.

Second question relates to Roth IRA's. Based on talking to my US tax adviser, as I currently have low income due to health issues he is suggesting I convert/transfer some of my IRA $$ each year to a Roth IRA. It seems pretty logical as the money transfered to the Roth will be taxed as income but will be at a low rate due to my situation. But the question we have is how will this be treated in the UK, will it need to be reported/declared as income and taxed at the higher rates the UK has? or are there other issues I need to be aware of?

thanks in advance for any replies,

tim

The year after we retired both myself and my wife rolled over our 401ks to IRAs and there is no implication. I’m pretty sure there is no tax implication in the UK either although we were in the USA at the time.  I am not sure if it needs to be reported to HMRC, maybe in the comments section. 

We also immediately started doing Roth conversions quite aggressively because Roth withdrawals are also tax free in the UK so getting that IRA money converted before moving back to the UK and before we started our UK and US state pensions meant paying taxes ahead of time at a lower rate.